Bryology - Masters First semester revision text.pdf

BRYOLOGY
FIRST SEMESTER, MSC BOTANY
DEPARTMENT OF BOTANY,
2021 – 2023
1/1/22
VIMALA COLLEGE,
THRISSUR

General characters of bryophytes
The term Bryophyta originates from the word ‘Bryon’ meaning mosses and ‘phyton’ meaning
plants. Bryophyta includes embryophytes like mosses, hornworts, and liverworts. These are
small plants that grow in shady and damp areas. They lack vascular tissues. They don’t
produce flowers and seeds, instead, reproduce through spores. The study of bryophytes is
called bryology.
Bryophytes are called “amphibians of the plant kingdom” because they are terrestrial plants,
but require water to complete their life cycle at the time of sexual reproduction.
• Plants occur in damp and shaded areas.
• The plant body is thallus like, i.e., prostrate or erect.
• It is attached to the substratum by rhizoids, which are unicellular or multicellular.
• They lack true vegetative structure and have a root-like, stem-like and leaf-like
structure.
• Plants lack the vascular system (xylem, phloem).
• Bryophytes show alternation of generation between independent gametophyte with
sex organs, which produces sperm and eggs and dependent sporophyte which contains
spores.
• The dominant part of the plant body is gametophyte which is haploid.
• The thalloid gametophyte is differentiated into rhizoids, axis and leaves.
• The gametophyte bears multicellular sex organs and is photosynthetic.
• The antheridium produces antherozoids, which are biflagellate.
• The shape of an archegonium is like a flask and produces one egg.
• The antherozoids fuse with egg to form a zygote.
• The zygote develops into a multicellular sporophyte.
• The sporophyte is semi-parasitic and dependent on the gametophyte for its nutrition.
REVISION NOTES -
General characters and systems of classifications of Bryophytes

• Cells of sporophyte undergo meiosis to form haploid gametes which form a
gametophyte.
• The juvenile gametophyte is known as protonema.
• The sporophyte is differentiated into foot, seta and capsule.
Classification of Bryophytes
❑ The term Bryophyta was first introduced by Braun (1864),
❑ However, he included algae, fungi, lichens and mosses in this group.
❑ The rank of division Bryophyta to this well-defined group of plants was first given by
Schimper (1879).
❑ Eichler (1883) was the first to divide Bryophyta into two groups:
Group I - Hepaticae
Group II - Musci
➢ Engler (1892) recognized Hepaticae and Musci as two classes and divided each
class into the following three orders:
❖ CLASS I Hepaticae divided into three orders:
Order 1 - Marchantiales
Order 2 - Jungermanniales
Order 3 - Anthocerotales
❖ Class II Musci divided into three orders:
Order 1 - Sphagnales
Order 2 - Andreaeales
Order 3 - Bryales
➢ Isolated characters of Anthoceros and related genera, Howe (1899) raised the
order Anthocerotales to the rank of a class and divided division Bryophyta into three
classes:
❖ Class I - Hepaticae
❖ Class II - Anthocerotes
❖ Class III - Musci.
➢ This system of classification was followed by Smith (1938, 1955), Takhtajan
(1953), Wardlaw (1955) and Schutser (1958), But preferred to call class Anthocerotes
as Anthocerotae.

➢ According to the Crandall-Stotler bryophytes have been divided into three
classes.
1. Marchantiophyta (Liverworts)
2. Anthocerotophyta (Hornworts)
3. Bryophyta (Mosses)
➢ International code of Botanical Nomenclature (ICBN) suggested in 1956-the
suffix-opsida should be used for the classes
➢ Already been proposed by Rothmaler (1951) for the classes of Bryophytes.
He changed the class names as:
Class I - Hepaticae as Hepaticopsida
Class II - Anthocerotae as Anthoceropsida
Class III - Musci as Bryopsida
➢ Proskauer (1957) suggested that the class name Antheoceropsida should be
Anthocerotopsida.
➢ Parihar (1965) and Holmes (1986) followed Proskauer’s system of classification and
divided Bryophyta into three classes:
Class I - Hepaticopsida
Class II - Anthocerotopsida
Class III - Bryopsida

➢ Campbell (1936) divided the class Hepaticopsida into:
▪ Order 1 - Takakiales
▪ Order 2 - Marchantiales
▪ Order 3 - Sphaerocarpales
▪ Order 4 - Jungermanniales
▪ Order 5 - Calobryales
➢ Classification of Bryophytes:
According to the latest recommendations of ICBN (International Code of Botanical
Nomenclature), bryophytes have been divided into three classes.
1. Hepaticae (Hepaticopsida = Liverworts)
2. Anthocerotae (Anthocertopsida = Hornworts)
3. Musci (Bryopsida = Mosses)
Fig: Classification of Bryophytes
A. Hepaticopsida (Liverworts): The name Hepaticopsida comes from the word
“hepatic” meaning liver. Liverworts come under this class.
Hepaticopsida is further divided into 4 orders:
1. Marchantiales (e.g., Riccia, Marchantia)
2. Sphaerocarpales (e.g., Sphaerocarpos)
3. Calobryales (e.g., Calobryum)
4. Jungermanniales (e.g., Pellia)

The main characteristics of the class Hepaticopsida are:
• Gametophyte plant is either thalloid or foliose
• In foliose forms, leaves are without midrib and dorsiventral
• Thalloid is dorsiventral, lobed and dichotomously branched
• Each cell of thallus contains many chloroplasts without pyrenoids
• Rhizoids are unicellular, branched and aseptate
• Sex organs are borne dorsally embedded in gametophytic tissues
• The sporophyte is made up of only capsule (in Riccia) or foot, seta and capsule (in
Marchantia)
• The columella is absent in the capsule
• Sporogenous tissues develop from endothecium
• Reproduction:
i. Asexual reproduction: It takes place by fragmentation or by the
formation of gemmae. Gemmae are produced inside gemma cups. Gemmae
are asexual buds, which are green and multicellular. The gemma cup
develops into a new plant after detaching from the parent plant
ii. Sexual reproduction: Antheridium (male organ) and archegonium (female
organ) may be present on the same thalli or different thalli. They produce
sperm and egg respectively. After fertilisation, zygote is formed. The
zygote develops into a diploid sporophyte, a few cells of the sporophyte
undergo meiosis to form haploid spores. These spores develop into haploid
gametophytes, which are free-living and photosynthetic
Some common examples are: – Liverworts:
o Marchantia
o Riccia
o Pellia
o Porella
o Sphaerocarpos
o Calobryum

B. Anthocerotopsida (Hornworts): There are around 300 species present in this class.
They are commonly known as hornworts. It has only one order i.e., Anthocerotales.
Examples: Anthoceros, Megaceros, Notothylas.
The main features are:
• The gametophytic body is flat, dorsiventral, simple thalloid without internal
differentiation
• Rhizoids are smooth-walled
• Each cell has one chloroplast with a pyrenoid
• Sex organs are present dorsally embedded in the thallus
• The sporophyte is differentiated into foot, meristematic zone and capsule
• Sporogenous tissues develop from amphithecium
• Pseudoelaters are present in the capsule
• The columella is present in the capsule, which originates from endothecium
• Reproduction:
i. Asexual reproduction: Vegetative propagation is by fragmentation of thallus
and by tubers, which are formed under unfavourable conditions
ii. Sexual reproduction: They reproduce sexually by waterborne sperm, which
travel from antheridium to archegonium. A fertilised egg develops into the
sporophyte. Sporophyte splits lengthwise to release spores which develop into a
gametophyte
Some common examples are: – Hornworts:
• Anthoceros
• Notothylas
• Megaceros
C. Bryopsida (Mosses): It is the largest class of Bryophyta with around 1400 species.
They are commonly called mosses. Examples: Funaria, Polytrichum, Sphagnum.

Bryopsida is further divided into 5 orders:
1. Bryales
2. Andreales
3. Sphagnales
4. Polytrichales
5. Buxbaumiales
The main features are:
• The gametophyte is differentiated into protonema and foliose gametophore
• Foliose is made up of stem as an axis and leaves without midrib
• Rhizoids are multicellular with oblique septa
• Sex organs are borne apically on stem
• Elaters are absent
• The sporophyte is differentiated into foot, seta and capsule
• Sporogenous tissues develop from endothecium
• Columella is present
• Dehiscence of the capsule takes place by separation of the lid
• Reproduction:
i. Asexual reproduction: Asexual reproduction is by budding and fragmentation of
secondary protonema
ii. Sexual reproduction: Antheridia and archegonia are present at the apical part
of leafy shoots. After fertilization sporophyte is produced, which is more
differentiated than liverworts. The gametophyte develops from the spores
Some common examples are: – Mosses: Funaria, Polytrichum & sphagnum

HEPATICOPSIDA - SPHAEROCARPALES
❑ Sphaerocarpales is a small order of Hepaticopsida, comprising only three genera, viz.
Sphaerocarpos, Geothallus and Riella.
❑ Members are commonly called "bottle-hepatics" because of the presence of a flask-
shaped or globose envelope (involucre) around each of the sex organs.
❑ A well-organised seta is absent in the sporophyte of the members of Sphaerocarpales.
❑ Bilaterally symmetrical & thallose gametophytes - no internal differentiation of tissues.
➢ ANATOMY
o Plant body - small, slightly dichotomously branched.
o Gametophyte - bilaterally symmetrical thallus. Male and female gametophytic
plants usually occur together in clumps. A several cells thick, broad midrib is
present in each gametophytic thallus. On margins, the wings of the thallus are only
one cell in thickness. Wings of the thallus are either entire or incised into leaf-
like lobes.
REVISION NOTES -
General account of the anatomy, reproduction, life history and
phylogeny of Sphaerocarpales, Marchantiales,
Jungermanniales, Calobryales, Anthocerotales, Sphagnales,
Andreales, Funariales and Polytrichales

o Sex organs, each surrounded by an ovoid or flask-shaped involucre, are present
on the dorsal surface of a midrib. They remain densely crowded. On the ventral
surface of the thallus are present many multicellular glandular hairs and smooth-
walled rhizoids. Tuberculate rhizoids and scales are absent.
o Thallus - lacks internal differentiation of tissues.
o All vegetative cells have chloroplast, except in rhizoids.
o Growth takes place by a row of wedge-shaped apical cells, which remain laterally
joined to one another. Each apical cell cuts off segments alternately from its
dorsal as well as ventral faces.
➢ REPRODUCTION
o Vegetative –
▪ Vegetative reproduction takes place by fragmentation and progressive
death and decay of the posterior portion of the thallus. When this death
and decay process reaches up to the place of dichotomy, the two branches
may survive and may continue to develop into two independent plants of
Sphaerocarpos. Sometimes, plants multiply vegetatively also by the
formation of proliferous outgrowth, either from the midrib or from the
lateral wings.
▪ It also takes place by gemmae developed between lateral and ventral scales.
o Sexual – oogamous, heterothallic.
Sex differentiation is attributed to sex chromosomes. Male plants differ from
female plants by their:
(i) smaller-sized gametophytes,
(ii) flask-shaped involucres, and
(iii) purple-tinged gametophytes.
• Development of antheridium - starts with a superficial dorsal cell, which enlarges
and becomes capitate. It is called antheridial initial. It soon divides into a basal
cell and an outer cell. The outer cell projects above the thallus. The basal cell
develops into antheridial stalk. The outer cell develops into the remaining major
part of the antheridium. The outer cell divides by successive transverse divisions
to form a vertical file of three cells, of which two upper cells are the primary

antheridial cells and develop further into antheridium proper. The lowermost third
cell forms the primary stalk cell. Each of the two primary antheridial cells divide
by two successive vertical divisions at right angles to each other and ultimately
forms four cells. A periclinal division in both tiers of four cells results into the
formation of outer four jacket initials and inner four primary androgonial cells.
Primary androgonial cells now divide by many successive divisions at right angles
to one another to form many cubical androgonial cells. Each cell of the last cell
generation of the androgonial cells divides diagonally into two androcytes. The
jacket initials divide anticlinally to form a well-organised jacket around the
antheridium. Each androcyte metamorphoses into a uninucleate, biflagellate
antherozoid. Free swimming antherozoids are spindle-shaped, curved or variously
coiled structures.
• Development of archegonium - starts with the arrangement of a dorsal cell called
archegonial initial. It first divides by a transverse division into a basal cell and an
outer cell. The lowermost part of the archegonium is formed by the basal cell,
while its remaining portion is formed by the outer cell. The outer cell first divides
by an asymmetrical vertical division to cut off a peripherial initial. Two more
unequal vertical divisions form two more peripheral initials. A primary axial cell
surrounded by these three peripheral initials now develops. All the three
peripheral initials now divide vertically to form six jacket initials surrounding the
primary axial cell. A transverse division in each jacket initial soon results in the
production of six neck initials present above a tier of six venter initials. An
archegonial neck of several cells in length and six cells in perimeter now develops
due to transverse division of neck initials and their daughter cells. In
Sphaerocarpos, the jacket of a mature venter of archegonium consists of 10 or
more cells in perimeter. Simultaneously, the primary axial cell divides transversely
into a primary cover cell and a central cell. The primary cover cell divides by two
successive vertical divisions to form four cover cells. Side by side, the central cell
divides transversely into a smaller upper canal cell and a lower canal cell. The upper
canal cell divides by two successive transverse divisions resulting into the
formation of four neck canal cells within the archeogonial neck. The lower canal
cell now divides asymmetrically to form a small venter canal cell and a large egg.

Soon, it is observed that the venter canal cell and neck canal cells of the mature
archegonium disintegrate to form a mucilaginous mass, and its cover cells are set
apart, resulting in the formation of an open passage for permitting and helping
the entry of the antherozoids to reach up to the egg.
• Fertilization – fusion of antherozoids and the egg, formation of zygote.
• Formation of sporophytes – zygote divides transversely to form upper epibasal
and a lower hypobasal cell, and both these cells again divide repeatedly. Two tiers
of the four cells in the epibasal half of the embryo develop ultimately into a
capsule of the sporophyte while the derivatives of the remaining two tiers develop
into the remaining parts of the sporophyte. Division of derivative cells results into
the formation of outer amphithecium and inner or central endothecium. A jacket
layer of capsule develops due to anticlinal division in the amphithecium.
Archesporium is endothecial in origin in Sphaerocarpos. The endothecium develops
into sporogenous tissue of the capsule.
Some sporocytes or spore mother cells of the sporogenous tissue divide
meiotically into four spores. Other cells of the sporogenous tissue remain sterile
and mature into sterile nurse cells. The function of nurse cells is to supply food
to the developing spores. Numerous chloroplasts are present in the nurse cells as
well as in the cells of the jacket layer of the capsule. Dispersal of spores takes
place after the death and decay of the jacket. A bulbous foot develops
simultaneously by the divisions in the basal part of the hypobasal half of the
embryo.

➢ LIFE HISTORY
HEPATICOPSIDA – MARCHANTIALES
❑ Most prominent order of class Hepatopsida.
❑ Commonly called "Chambered hepatics"
❑ According to Shiv Ram Kashyap,
Comprises 3 families:
▪ Ricciaceae
▪ Monocleaceae
▪ Marchantiaceae

➢ ANATOMY
o Plant body – gametophytic.
o Thallus - dichotomously branched.
o Gametophyte - prostrate, dorsiventral thalli. Photosynthetic region or Dorsal surface
is green with midrib and contains several air chambers. Each air chamber opens
outside by a well-defined air pore. Storage region or Ventral surface contains scales
and rhizoids (smooth-walled or tuberculate). Ventral region has parenchymatous
storage tissue filled with oil bodies in mucilage cells.
o Gemmae are present sometimes in a cup-shaped structure called gemma cup.
o Sex organs - antheridia & archegonia scattered along midrib or on raised receptacles.
o Seta are short or absent in sporophyte.
o Green tissue confined to dorsal region of the thallus.
➢ REPRODUCTION
 Vegetative -
1. Progressive death and decay – start from the posterior part of the thallus and the
older parts die, reaches upto the dichotomy.
2. Adventitious Branches - In species like Riccia fluitans, adventitious branches
develop from the ventral surface of the thallus. These branches, on separation from
the main thallus, may develop into new thalli.
3. Apex of thallus - The apex of the thallus grows down into the moist soil and
becomes thick at the end of the growing season. It develops into a new thallus when
favorable conditions return in the next season.

4. Apex of rhizoids - The apical part of the rhizoid has the ability to form a thallus.
in much the same way as a germinating spore forms a germ tube and then a young
thallus.
5. Tubers - Thalli sometimes develop perennating tubers, which have the ability to
survive in unfavourable conditions. On return of favourable conditions, these tubers
may grow into new thalli.
6. Gemma – develop in cup-shaped receptacles known as gemma cups, which are formed
on the gametophyte body. Gemmae and gemma cups are gametophytic organs unique
to some Marchantiopsida species.
 Sexual - The two sex organs in Riccia are antheridia and archegonia. In monoecious or
homothallic species, both antheridia and archegonia develop on the same thallus. But in
dioecious or heterothallic species, antheridia and archegonia develop on separate thalli.
1. Development of antheridium - starts from a single superficial initial cell. This cell
can be identified due to its upward growth, and dense contents in relation to its
neighboring cells on the dorsal furrow, a few cells behind the apical cells. It is known
as antheridial initial. Soon it becomes papillate and divides transversely into a lower
basal cell and an outer cell. The basal cell remains embedded in the thallus and forms
the stalk of the antheridium. The outer cell projects slightly above the thallus,
undergoes several divisions and forms the rest of the antheridium. Repeated divisions

in the primary androgonial cells give rise to small cubical fertile androgonial cells, the
last generation of which are known as androcyte mother cells. Each androcyte mother
cell divides diagonally into two triangular androcytes. Each androcyte is uninucleate
and metamorphoses into an antherozoid. During the process of metamorphosis, each
androcyte contains a prominent nucleus and an extranuclear granule called
blepharoplast. The blepharoplast granule develops in the peripheral part of the
protoplast of androcyte. Soon the androcyte loses its triangular shape, and becomes
a spherical body.
A mature antherozoid is uninucleate with a homogeneous nuclear portion, which
occupies the major part of the antherozoid. Blepharoplast, the extranuclear granule,
ends in a head bearing two long flagella. The antherozoid moves with the help of its
flagella. Both the flagella are attached at the same level on opposite sides. The
function of one flagellum is to help in propulsion while the other flagellum helps in
rotation and also in changing the direction of the antherozoid. A mature antheridium
consists of a small stalk and a globular or club-shaped body.
2. Development of archegonium - starts from a single superficial cell on the dorsal
surface of the thallus quite close to the apical cell. This is called archegonial initial,
which soon becomes papillate and divides by a transverse division into an outer cell
and a basal cell. The outer cell ultimately forms the body of the archegonium while
the basal cell finally develops into the embedded portion of the archegonium.
A mature archegonium is a flask-shaped, long-necked structure. It remains attached
to the thallus tissue on the dorsal surface by a short stalk. It contains a swollen
venter and an elongated neck. The neck is a single-layered, tube-like structure made
up of 6 to 9 tiers of elongated cells arranged in six vertical rows and surrounding a

fine narrow canal. At the upper part of the neck are present four cover cells. The
canal of the neck contains four neck canal cells. The venter contains a one-layered
wall and encloses a small ventral canal cell and ventral canal cell disintegrate and form
a mucilaginous mass. Due to the pressure of this mucilaginous mass, all the four cover
cells of the neck separate apart from one another, and some of the mucilaginous mass
also extrudes from the tip of the archegonial neck.
3. Fertilization - The mucilaginous mass, formed by the disintegration of neck canal
cells and venter canal cell imbibes water, swells up and exerts a pressure on cover
cells to separate. Due to all these activities, the canal is open up to the venter. This
mucilaginous mass also attracts spermatozoids swimming in the surface film of water.
The attraction is a chemotactic phenomenon due to the presence of some proteins
and inorganic salts in the mucilage. The spermatozoids are guided up to the egg due
to this chemotactic phenomenon. A spermatozoid (X) fuses with the egg (X), resulting
into the formation of a diploid structure called zygote (2X). The zygote soon secretes
a wall, increases in volume and finally occupies the entire lumen of the venter.
4. Formation of sporophyte –
The diploid zygote is the first cell of the sporophytic generation or asexual
generation. It soon secretes a cell wall of its own, enlarges and almost fills the cavity
of the venter. Cells of the venter start dividing periclinally and then also anticlinally
to form a bilayered calyptra. Simultaneously, the zygote divides first by a transverse

division to form two almost equal-sized cells. Both these cells now divide vertically to
form a four-celled embryo or quadrant-stage. Soon follows one more vertical division
at right angles to the first one and thus results an eight-celled or octant stage of
the embryo. The young eight-celled embryo now divides in all the planes without any
definite sequence to form a multicellular (20 to 40-celled) spherical mass of cells. It
now divides periclinally into a layer of amphithecium and an inner mass of cells, which
represents the endothecium. The endothecial archesporium, which is the first cell
generation of sporogenous tissue, divides and redivides several times to form a large
mass of sporogenous cells. All these cells are potential sporocysts or spore mother
cells. Each of these spore mother cells is diploid, divides reductionally and forms four
haploid spores.
Sporogenesis: Formation of haploid spores from the diploid spore mother cells is
called sporogenesis. The sporogenesis starts with the contraction of cytoplasmic
contents of spore mother cells or sporocysts. Each spore mother cell divides by two
successive divisions and develops into a tetrad of spores. It also results in a reduction
division, thereby the chromosome number is reduced to half, i.e., each diploid spore
mother cell changes into four haploid spores arranged first in the form of a tetrad.
The cell plate is incomplete during the first division, and after the completion of the
second division, the cell plates delimiting four spores are formed simultaneously. All
the four spores of a spore tetrad remain opposed to one another and also remain
surrounded by the wall of the spore mother cell till the maturity of the spore wall.

5. Germination of spores - Spores in Riccia are dispersed without any definite
mechanism, simply
(i) by disorganisation of wall of capsule or sporogonium, and
(ii) by decaying of the surrounding tissue of the thallus.
At the time of germination, a spore absorbs some water swells, and starts producing
a germ tube. Usually, the spores remain adhered in tetrads in the initial stages of
their germination. The germ tube is an elongated structure and remains filled with
chloroplasts and oil globules. Its cell contents start accumulating towards the apex.
Soon the apical part of the germ tube is separated by a transverse division. The so-
formed cell now again divides by one more transverse division and then by a vertical
division in both these cells, resulting into a 4-celled body or germ disc. From the
lowermost part of the germ tube also develops the first rhizoid. Out of the four cells
of the germ disc, one starts functioning as an apical cell with two cutting faces. The
activity of this apical cell results in the formation of a multicellular young thallus.

➢ LIFE HISTORY
HEPATICOPSIDA - JUNGERMANNIALES
Jungermanniales is the largest order of class Hepaticopsida in the division Bryophyta. This
order contains 244 genera and more than 9000 species. Members of Jungermanniales are
known as leafy liverworts. Because the gametophytes of this order are mostly foliose type
and they are differentiated into stem and leaves.
In some genera, gametophytes are thallose types like those of Marchantiales. Intermediate
forms between thallose and leafy types are also noted among some members of this order.
But the presence of any air chamber or any internal tissue differentiation like the
gametophytes of Marchantiales is absent. The gametophytes bear only smooth-walled
rhizoids. Scales are absent.

➢ ANATOMY
Structure of gametophyte of Jungermanniales:
The gametophyte of Jungermanniales is the plant body. The plants are thalloid, except
Fossombronia.
External morphology:
The plants are thalloid in which midrib is present (Pellia) but maybe absent (Riccordia).
In Fossobronia, the plant body is erect and foliose, which is divisible in stem and leaves.
In Pellia, the gametophytic plant body is thin, dorsiventrally flattened, prostrate, and
dark bright green in color. Leaves are arranged in lateral margins; a clear differentiation
is observed in Fossombronia. Scales and rhizoids are absent in most of the plants. But in
Pellia, numerous simple, smooth-walled, unicellular rhizoids are present irregularly on the
mid-ventral surface of the thallus.
Internal morphology:
The internal structure of the thallus is very simple. No tissue differentiation is observed
in the thallus. Simple, thin-walled chlorenchymatous tissues are present between the
upper and lower epidermis. From the lower epidermis rhizoids are arise in Pellia.
A single large apical cell situated in the apical notch brings out the growth of the thallus.
Sexual reproductive structures of Jungermanniales:
In some species, sex organs are developed at specific branches called antheridial and
archegonial branches. Fossombronia is heterothallic, hence the male and female organs
develop at separate thallus. In Pellia, the thallus may be monoecious (Pellia epiphylla) or
maybe dioecious (Pellia endivaefolia). Sex organs (antheridium and archegonium) are
borne on the thallus.

Structure of the sporophyte:
The sporophyte consists of the foot, seta, and capsule. The foot is a small bulbous type
and the seta is very short. The capsule is made up of 2 layers of thick jacket and inner
side elaterophores. In elaterophores, elaters and spore-tetrads are present.
➢ REPRODUCTION
Antheridium:
Antheridium is the male sex organ. In antheridium, any cell behaves like a superficial cell
and divide by transverse division to form an upper cell and a basal cell. Generally, the
basal cell is inactivated and the upper cell divides to form a stalk cell and a primary
antheridial cell.
Stalk cell divides to form 2 celled stalk, while antheridial cell divided by transverse
division and oblique division through which peripheral cells and central cells are formed.
Peripheral cells are divided and a one-celled thick jacket is developed, while central cells
divide to form antherozoid mother cells. Antherozoid mother cells produce antherozoids
which are spiral, biflagellate, uninucleate.
In such a way, mature antheridium is made up of a 2 celled stalk, and club-shaped
structure.
Archegonium:
Archegonium is the female sex organ developed at the female thallus. In Pellia, the group
of archegonia is protected by an involucre (an outgrowth of the thallus tissue developing
from the base of the archegonium).

In archegonium, any cell behaves like a superficial cell which is divided by transverse
division to form an upper cell and a basal cell. Basal cell forms stalk. While upper cell
divides by oblique division to form peripheral cells and central cells. Peripheral cells
continue to divide to form jacket and central cell divide to form primary cover cell and
central cell. The primary cover cell produces 4 cover cells and the central cell forms a
primary neck initial and a primary venter initial. Neck initial divides to form neck canal
cell and primary venter initial divides to form one ventral canal cell and an egg.
In such a way, mature archegonium is consists of 4 cover cells, 6-8 neck canal cells, one
ventral canal cell, and an egg.
Fertilization:
When archegonium matures and the antherozoid is released towards the archegonium,
neck canal cells and ventral canal cells dissolved and water enters in neck portion. From
the neck of the archegonium, some salts or proteins are excreted which stimulates the
antherozoids to move in that direction. Then the antherozoid enters the archegonium
male nucleus fused with egg to form a zygote.

Development of the sporophyte:
A zygote is the first cell of the sporophyte, immediately after fertilization, the zygote
increases in size. The zygote is divided by transverse division to form epibasal cells and
hypobasal cells. Hypobasal cell is inactivated, while epibasal cell divides through 3
transverse, one longitudinal, and one vertical division. In this process, 4 tiers of 4-4 cells
are formed. Upper 2-tiers form capsule. In upper tiers, periclinal division takes place
through which outer amphithecium and inner endothecium are formed.
Amphithecium develops in the outer jacket, while outer endothecium develops in the
inner jacket. Inner endothecium changed into archesporial tissue, in which some are
fertile and some are sterile.
Fertile cells undergo meiosis to form spore-tetrad but sterile cells are present either
at the lower portion (Pellia) or at the upper portion (Riccardia). These cells are elongated
and form elaterophores. The elaterophores produce elaters. The elaters are spindle-
shaped elongated structures provided with 2-3 spiral thickening bands.
Dehiscence of capsule:
When the capsule is matured then the upper jacket is dried away while the lower jacket
is moist, so due to contraction and expansion capsule is opened into 4 slits. Its opening
is similar to a flower opening.

Examples of Jungermanniales: Pellia, Porella, Fossombronia, Riccardia, etc.
➢ LIFE HISTORY
HEPATICOPSIDA – CALOBRYALES (Haplomitriales)
They are characterized by prostrate, simple or branched, leafless stems and erect, leafy
branches of a radial organization. The order consists of a single genus, Calobryum and 12
species, most of them occupying restricted ranges in apparently relic areas indicative of an
ancient origin and dispersal. The order is considered primitive in comparison with the
Jungermanniales, in which the leafy axis tends to be prostrate and the under leaves
reduced.
➢ ANATOMY
Morphological structure of Gametophyte
The plant body is gametophyte which is differentiated into creeping leafless basal,
branched rhizome, from which arise the erect leafy shoot with their leaves radially
disposed (known as gametophore). The gametophore is bright green or yellowish green

in colour mostly 8 - 25mm tall. A newly formed branch may creep over the substratum
for a time and then abruptly turns upwards, grows erect and bears the leaves. The
branches are dimorphic and exogenous and intercalary in origin. The rhizome and the
creeping part of the erect branch completely lack rhizoids. The absence of rhizoids and
rhizomatous gametophyte are the noteworthy features in which Haplomitrium
(Calobryales) differs from all the Hepaticeae except Takakia. In some species of
Haplomitrium (H. minioides) one or more vertically descending leafless branches arise
from the base of the erect
leafy shoot, grow vertically downward and penetrate the substratum These are
known as stolon or flagella.
The leaves are simple, entire, dorsiventrally flattened, soft textured and without midrib.
They are radially disposed and arranged in 3 vertical rows on the erect gametophore.
Schuster (1967) reported that the leaves are usually anisophyllous, occasionally
isophyllous. Anisophyllous species are H blumii. H adinm and H. giganteum etc. and
isophyllous species are H. gibbsiae, H. mnioides and H. intermedium. In anisophyllous
species the leaves of one rank (out of three) are smaller in size.

Anatomy of Leaf - The leaves are one-layered thick (unistratose) except for the basal
part which is two or four cells in thickness (multistratose). The leaves are composed of
uniform parenchymatous cells containing many oil bodies per cell beside chloroplasts.
Stem anatomy - The transverse section of stem shows two distinct regions outer green,
starch rich cortex, and inner colourless central strand. The outermost layer consists of
approximately isodiametric cells with a very thin cuticle and contains more plastids, than
deep lying cells. Campbell (1959) reported. Cell organelles are abundant. Some peripheral
cortical cell grows into short 2-3 celled slime papillae of non-beaked type with a clavate
apical cell. The papillae secrete mucilage. The central strand consists of smaller
elongated leptodermis cell and is 10-15 cells in diameter. These cells contain no cell
organelles and devoid of cytoplasm resembling the hydroids of mosses. Numerous pores
occur between the adjacent conducting cells. A clear continuity in size and shape exists
between cortical cells and central strand cells.
Apical Growth - Growth of the stem occurs by a pyramidal apical cell with three cutting
faces, one slightly narrower than the other two.
➢ REPRODUCTION
Asexual reproduction is unknown in the Calobryales.
Sexual Reproduction - The gametophores are dioecious. Sex organs are antheridia &
archegonia produced on the expanded apex of the erect shoots of different plants.
Antheridia - The antheridia are densely-packed in male receptacle at the apex of the
main stem and resemble the gametophore of mosses. Each antheridium is sub -globose
in shape and has a very long stalk. Antheridial development in Calobryum blumii begins by
a transverse division of the antheridial initial into a basal cell embedded in the thallus
and an outer cell which Project above the thallus. The outer cell divides transversely
into a primary antheridial cell developing into the body of the antheridium and a primary
stalk cell forming the multicelled stalk of the antheridium. Three successive vertical
divisions of the primary antheridial cell result in three jacket initial enclosing a single
Primary androgonial cell. The first division of the primary androgonial cell is transverse.
The two daughter cells so formed divide transversely and longitudinally and finally

become androcyte mother cells which by repeated mitotic divisions develop into
antherozoids.
Archegonia - The archegonia are borne singly at the apex of the main shoot and are
usually protected by the perichaetial leaves. Female plants of Calobryum have the
archegonia developing from about half a dozen recently formed segments cut off from
the apical cell and finally the apical cell itself develops into an archegonium. The sequence
of archegonial development is similar to that in an antheridium. The archegonial initial
by three successive vertical divisions result in three jacket initials enclosing a primary
axial cell. The primary axial cell functions directly as central cell and by transverse
divisions form a ventral canal cell and an egg. Vertical division of only one of the three
jacket initials result in an archegonial neck composed of only four rows of cell. Thus, the
neck of an archegonium is very long, twisted vertical row of 16-20 neck canal cells.
Towards maturity the cells of the single-layered venter wall divide periclinally. resulting
2-3 cells thick Venter wall. There is total lack of any leaf derived protective sheath such
as the perianth around the archegonial cluster. Thus, archegonia are naked.
Shoot Calyptra: - Following fertilization, the Venter wall cells start dividing extensively,
by periclinal divisions resulting in a cylindrical, fleshy green to yellowing green, brittle
massive 15-17 mm long calyptra surrounding the developing sporophyte. In some species
the cells near the Venter become meristematic and divide actively resulting in a massive
calyptra. It is called ‘Shoot Calyptra’. The sterile archegonia are elevated on the shoot
calyptra.

Sporophyte: - Sporophyte is terminal in position and surrounded by the massive shoot
calyptra when young. The mature sporophyte is differentiated into the foot, the seta
and the capsule. The seta of Haplomitrium is 25-30 mm long, massive and solid. The
capsule is cylindrical 4 to 5 mm long deep-brown. The foot is acuminate in form. The
capsule wall is unistratose except the tip region which is bi or tri seriate. Inside the
capsule wall, the sporogenous tissue is differentiated into spores and elaters. The spores
are 18- 30u and elaters 6- 10 u in diameter. The spore: elater ratio is 3 :1. Elaters are
long, very slender, gradually tapered to their tips. They are bispiral. The spore wall has
numerous, short blunt papillae. The mature capsule dehisces by a single, longitudinal slit
along one side or by 4 longitudinal slits along 4 discrete lines of dehiscence.
ANTHOCEROTOPSIDA – ANTHOCEROTALES
The class Anthocerotopsida (Anthocerotae) consists of a single order, the Anthocerotales
and a single family, the Anthocerotaceae, 6 genera and 301 species.
This group differs in many respects from the other Bryophyta. However, the group is placed
intermediate between Hepaticopsida (Hepaticae) and Bryopsida (Musci). The group is
considered to be very important from the point of view of its morphology, because of its
intermediate position between the two important groups, the Hepaticopsida and Bryopsida.
➢ ANATOMY
The most characteristic features of the group are as follows: The gametophytic plant
body is thalloid and dorsiventral. The rhizoids are simple and smooth walled. Tuberculate
rhizoids and ventral scales are altogether absent.

The tissues of the thallus are not differentiated. Each cell of the thallus possesses a
large chloroplast and a conspicuous pyrenoid within it.
The antheridia are endogenous, i.e., they arise from the hypodermal cells of the thallus
on the dorsal side of it. The antheridia are developed within the antheridial chambers,
singly or in groups on the dorsal side of the thallus.
The archegonia are found in sunken condition on the dorsal side of the thallus.
The sporogonium arises from the dorsal side of the thallus. It is elongated and cylindrical
in structure. It consists of foot, meristematic region and capsule. It possesses
intercalary meristem, and continues its growth throughout the growing season. The wall
of sporogonium contains chlorophyll. The central sterile portion is columella, which is
surrounded by sporogenous tissue and spores. The elaters are also present.
The sporogenous mass develops from amphithecium and arches over the columella.
Internal structure of the thallus:
The anatomy of the thallus is quite simple. Internal to the upper and lower epidermis
there are simple, parenchymatous cells. The cells of parenchyma are isodiametric and
uniform. Air chambers and air pores are absent. Each cell contains a big chloroplast which
possesses a single pyrenoid in its centre. The chloroplasts are lens shaped. The
chloroplasts of the superficial cells are longer than the chloroplasts of the other cells.
➢ REPRODUCTION
The reproduction takes place by means of (1) vegetative and (2) sexual methods.
1. Vegetative reproduction:
(a) By progressive growth and death of thallus: The vegetative propagation takes place
by progressive growth and death of the older part of the thallus reaching dichotomy.
But this method is not so common in Anthoceros as in Riccia and Marchantia.
(b) By tubers: In certain species of Anthoceros, the thallus becomes thickened at
several places on the margins. Such marginal thickenings are called, the tubers. These
tubers are perennating structures. They survive in the drought conditions. On the advent
of the favourable conditions, they develop into new thalli. The tubers are formed in A.
laevis, A, tuberosus, A hallii, A. pearsoni and A. himalayensis.

(c) By gemmae: In some of the species of Anthoceros, the gemmae have been found.
The gemmae have been recorded from the species, A. glandulosus, A. formosae, etc.
Each such gemma develops into a new thallus.
(d) By persistent growing apices: According to Campbell the thalli of the species A.
pearsoni and A. fusiformis become completely dried up in summers, leaving growing
apices with adjacent tissues. These apices face the drought conditions. On the approach
of favourable conditions, these apices develop into new thalli.
2. Sexual reproduction:
The species of Anthoceros may be homothallic (monoecious) or heterothallic (dioecious).
Some of the homothallic species are- A. fusiformis, A. punctatus, Kashyap (1915, 1929)
has recorded, A. himalayensis as a dioecious (heterothallic) species, but Mehra and
Handoo (1953) have reported the same as monoecious (homothallic) but protandrous. The
heterothallic species are, A. pearsoni, A. halli, A. erectus and others. The sex organs,
i.e., antheridia and archegonia are found embedded in the tissues of the dorsal side of
the thallus.
Development of antheridium: The antheridia are produced singly or in groups in the
antheridial chambers. The development is endogenous. Though the antheridium develops
from a superficial cell, yet it is enclosed within the antheridial chamber which does not
open out by any opening.
A dorsal superficial cell of the thallus, situated near the growing apex divides periclinally
giving rise to two daughter cells. According to Cavers, Campbell and Haupt the superficial

cell divides transversely and not periclinally. The upper daughter cell acts as roof initial
and the lower one as antheridial initial.
Eventually, a mucilage filled space appears in between the roof initial and antheridial
initial. This mucilage cavity enlarges in size and ultimately becomes the antheridial
chambers. The roof initial is nothing to do with the development on the antheridium.
It divides and redivides several times anticlinally and periclinally giving rise to a two
layered roof of the antheridial chamber. Simultaneously, the antheridial initial develops
into a single antheridium or in a group of antheridia.
The antheridial initial divides twice by vertical walls intersecting each other at right
angles, giving rise to four cells. This is followed by another transverse division giving rise
to two tiers of four cells each. The four cells of the upper tier divide transversely giving
rise to eight cells, the octant stage.

All of the cells of octant stage divide periclinally giving rise to eight outer primary jacket
cells and eight inner primary androgonial cells. The four cells of the lower tier develop
into a stalk of the antheridium consisting of the four rows of the cells.
The so formed androgonial cells divide repeatedly. The last generation of these cells are
androcyte mother cells. According to Bagchee (1924) each androcyte mother cell divides
diagonally producing two androcytes. Each androcyte metamorphoses into a spindle like
biciliate antherozoid.
Structure of mature antheridium and its dehiscence: The mature antheridium is stalked
and club shaped. The stalk of the antheridium may consist of the mass of cells, e.g., A.
laevis, or it may consist of the four rows of the cells, as in A. erectus and A. punctatus.
The antheridium proper is covered by a single layered jacket. Inside the jacket, there
are numerous androcytes which are to metamorphose into antherozoids.
On the maturation of the antheridium, the roof of the antheridial chamber
disintegrates, with the result the antheridia are exposed to outside. Soon after, the
antheridia absorb water and burst at their apical ends, giving way to the antherozoids
to move outside. Sometimes the androcytes come out in the form of an opaque mass at
the opening of the antheridium. Within few minutes they metamorphose into the
antherozoids.
The antherozoids: The antherozoid is spindle like and biciliate. The cilia are attached to
the anterior end of the body. Sometimes just near the attaching point of the flagella to
the body, the blepharoplast is visible. The antherozoids swim in the water by the lashing
moment of their flagella.
Development of archegonium: The archegonia are found embedded in the thallus. They
remain in direct contact of the vegetative cells of the tissue of the thallus lateral to
them. They do not possess jacket sterile cells around them. The development of
archegonium begins from a single superficial cell. This cell becomes prominent and acts
as archegonial initial.

According to Mehra and Handoo (1953), this has been established that the archegonial
initial functions directly as a primary archegonial cell. Formerly it was believed
(Campbell) that it divides, and produces two cells, the primary archegonial cell and
primary stalk cell. The archegonial initial first divides vertically, producing three jacket
initials which surround an axial cell.
The axial cell divides transversely, producing a cover initial and a central cell.
Thereafter, the central cell divides by a transverse wall, giving rise to a primary canal
cell and a primary venter cell. The primary canal cell divides repeatedly, producing a
linear file of 4-6 neck canal cells. The primary venter cell divides once transversely,
giving rise to two cells, a ventral canal cell and an egg (oosphere).
Comparatively, the neck canal cells are narrower than the venter canal cell and the egg.
Eventually, the three jacket initials also divide by transverse walls. The further
development of the jacket layer is not at all clear. Since the cells on the lower face of
the egg have been derived from the archegonial initial they cannot be treated as a part
of archegonium.

Structure of archegonium: On the maturation of the archegonium, the venter canal cells
and neck canal cells become gelatinized. Thus, a mature archegonium is flask-like in
shape, without neck canal cells and with an egg (oosphere) in its venter. At the top of
the neck of the archegonium there are four cover cells, which become separated from
the archegonium, as soon as the gelatinization of the venter and neck canal cells is over.
Fertilization (syngamy): Prior to fertilization, the cover cells become detached from the
archegonium, and the neck canal cells become gelatinized. Through the medium of water,
the antherozoids enter the mouth of archegonium. The antherozoids are attracted
chemotactically. Ultimately, one lucky antherozoid penetrates the egg, and the
fertilization is affected. The male and female nuclei unite to each other, producing a
zygote (oospore), zygote is 2n, and this is the beginning of the sporophytic stage.
Development of sporogonium: After fertilization, the zygote secretes a cellulose wall
around it and enlarges in size still it completely fills the venter of the archegonium. The
first division of the zygote is vertical. But according to Pande (1932) and Bhardwaj
(1950), in certain cases this divides transversely.
With the result of the first vertical division, the daughter cells are produced, which are
subjected to a transverse division producing four cells of equal or unequal size. When
the cells are unequal in size, definitely the cells towards the neck of the archegonium
are larger cells.
These cells again divide vertically, developing eight celled embryo, four cells in each tier.
The upper tier of four cells divides transversely. This way the three tiers of four cells
each have been produced. The lowermost tier produces the foot, the middle tier
produces partly the foot and mainly the seta and the upper-most tier produces the
capsule.
The cells of the lowermost tier divide regularly or irregularly many times, producing the
bulbous foot. The foot is haustorial in nature, which absorbs food from the tissue of the
gametophyte.
The uppermost tier of four cells, divides once or twice transversely, producing two or
three tiers of cells. Now the cells divide periclinally, giving rise to an outer layer the
amphithecium and the central mass of cells the endothecium. In the young sporogonium,
the columella consists of four vertical rows of the cells, the endothecium.

In the young sporogonium, the columella consists of four vertical rows of the cells, but
later on it is made up of sixteen rows of cells. According to Bhardwaj (1958) in A.
gemmulosus the columella consists of 36 to 49 vertical rows of the cells. The
amphithecium divides periclinally producing the outer sterile layer of the jacket initials
and an inner sporogenous tissue, the archesporium.
The jacket initials divide again and again periclinally producing the 4 to 6 layered wall of
the capsule. The outermost layer develops into the single layered epidermis. The
epidermal cells are cutinized. The stomata may or may not develop on the epidermal
layer. The rest of the layers, beneath the epidermis develop in normal chlorenchyma.
These chlorophyllous cells, however, help in synthesizing the food.
The layer of archesporium developed by periclinal division overarches the columella. The
sporogenous layer may be one to four celled in thickness in its further development. In
Anthoceros hawaiensis it remains one celled in thickness; in A. pearsoni and A.
himalayensis it may become two, three or even four cells in thickness.
In younger stages all the cells of sporogenous tissue remain somewhat rectangular in
shape.
Later on, the sporogenous tissue becomes differentiated into two types of cells, i. e.,
(i) the sporocytes (spore mother cells) and (ii) the sterile cells (pseudoelaters).
The sporocytes or spore mother cells undergo the reduction division, each producing a
tetrad of four spores. These spores are haploid. The spores, which develop in the upper
part of the capsule, mature first. Each spore contains a nucleus and a chloroplast.
The sterile cells soon divide obliquely or transversely producing three to five celled
pseudoelaters. On maturity, the pseudoelaters lose their protoplasm. The walls of the
elaters may be smooth, irregularly thickened or with spiral thickenings. Such
thickenings, vary from species to species. The pseudoelaters help in the dehiscence of
the spores and behave like true elaters. In earlier stages their function seems to be
nutritive.
The sporogonium and its dehiscence: The capsules arise from the thalli in the form of
small horny structures. Usually, they are two to three centimetres long. But in some
species, they range even from five to fifteen centimetres in their height and because

of their horny appearance, the species are called ‘hornworts’. The mature sporogonium
consists of a bulbous foot and a projecting, slender and erect capsule. There is a
meristematic zone above the foot, instead of seta.
The bulbous foot consists of parenchyma. It remains penetrated in the thallus and acts
as haustorium. The superficial cells of the foot are palisade like. The space in between
the foot and the capsule is occupied by a meristematic zone. The cells of this zone
divide throughout unless and until the food is completely exhausted. This way, the
capsule increases in length. The capsule increases in height even after maturation.
The cells developing from the meristem become differentiated into jacket layer,
columella and archesporium. Thus, the upper part of the sporogonium matures first,
and the basal part remains young. The capsule does not mature at the same rate in all
parts of it. The mature spores liberate from the upper part of the capsule whereas, in
the basal part still the cells are in embryonic condition.
The main capsule consists of many important parts. The central region of the capsule is
occupied by a sterile columella. According to Campbell (1924), in A. fusiformis the

columella acts as water conducting tissue. However, this function of columella in other
species is not very certain. The main function of columella is to give the mechanical
support to the sporogonium. It also helps in the dispersal of the spores.
The columella remains surrounded by sporogenous tissue. In the region just above the
foot the archesporium is single layered and too young. The tip region of the sporogonium
possesses mature spores and elaters. The wall of the capsule consists of the four to six
layers of the parenchymatous cells. The outermost layer is epidermis, which is
interrupted by stomata at several places. The epidermal cells are cutinized.
The stomata open in the intercellular spaces of the chlorophyllous cells. Usually, each
cell possesses two chloroplasts. The process of photosynthesis takes place by means of
chloroplasts and stomata. This way, the organic food is synthesized for the sporogonium.
However, the sporogonium remains dependent upon the thallus for the supply of water
and other nutrients throughout its life.
On maturation, the tip of the sporogonium becomes black or dark-brown in colour. The
capsule divides at this stage. The tip of the capsule shrivels up by losing water. The
dehiscence of the capsule is more or less dependent upon the loss of water. This way
the dry atmosphere helps in the dehiscence of the capsule.
The dehiscence begins from the tip region of the capsule. At first a small longitudinal
slit appears, which widens and enlarges. The pseudoelaters are hygroscopic in nature.
They begin to twist after the exposition of the internal mass the outside. Due to this
twisting of the pseudoelaters the pressure is exerted on the jacket layer, and it bursts
liberating the spores in the atmosphere.
According to species, the dehiscence takes place by means of one to four longitudinal
slits. The valves of the capsule curve backward and ultimately, on drying up they become
twisted around each other. The liberated spores are dispersed by wind from one place
to another.
The spore: In earlier stages the spores are found to be arranged in tetrads. After being
separated from each other they are dispersed. Each spore is somewhat spherical and
possesses two wall layers. The outer wall layer is exine and the inner wall layer is intine.
The intine is smooth and thin, whereas the exine is somewhat thick and ornamented. The
colour of the mature spores varies from species to species; this may be yellow, brown,

dark brown or black. Each spore possesses a single nucleus, a colourless plastid, few oil
droplets and food material within it.
Germination of spore:
After their liberation from the sporogonium the spores undergo a period of rest prior
to germination which ranges from few weeks to few months. The exine of the spore
ruptures, and the intine comes out in the form of a germinal tube or protonema of
variable length.
Development of young gametophyte: The chlorophyll present in the chloroplast of the
spore passes in the germinal tube along with oil droplets and food material. Thereafter
the germinal tube divides transversely at its apical end. This division is followed by
another transverse division. Soon after, the so formed two cells divide by longitudinal
intersecting walls and the quadrants are resulted. At the terminal end a growing point
with an apical cell appears which by producing several segments develops into the young
gametophyte. Soon after mucilage slit develops on the ventral side of the thallus. Some
of the marginal cells of the young thallus develop into smooth walled rhizoids. The Nostoc
sp. penetrates the thallus through the mucilage slits, which later on form the colonies
of the same.

➢ LIFE HISTORY
Inter-relationships of Anthocerotopsida: The Anthocerotopsida differ from other
bryophytes in a number of respects. These differences are:
• Among Anthocerotopsida the cells are with large chloroplasts and each chloroplast
contains a pyrenoid.
• In this group the development of antheridia takes place from hypodermal cells on the
dorsal side of a gametophyte.
• The archegonia of this group are almost completely embedded in the gametophyte.
• The growth of sporophyte is indeterminate because of a meristematic region continually
adding to the base of capsule.
• Because of the differences mentioned above the class has been placed in between
Hepaticopsida on one hand and the Bryopsida on the other.

The other features of special interest of Anthocerotopsida are:
• The gametophytes are thallose, somewhat lobed or radially dissected, and sometimes
show a tendency of dichotomous branching.
• The gametophytes are always dorsiventrally differentiated and possess numerous
smooth-walled rhizoids on the ventral surface.
• The ventral surface is devoid of scales and mucilage hairs.
• Lateral margins of most of the genera of this group (except of Dendroceros) are more
than one cell in thickness.
• There is no internal differentiation of tissues.
• The ventral portion of a thallus has mucilage-filled intercellular cavities on the dorsal
side and opening to the surface by narrow slits. These cavities generally contain Nostoc
(a blue green alga) colonies in them.
• The pyrenoids of Anthocerotopsida are not homologous with those of green algae
(Chlorophyceae) since they consist of a crowded mass of 25 to 300 disc or spindle shaped
bodies (McAllister, 1914, 1927).
• The growth of a thallus is initiated by a single apical cell with two cutting faces (except
in Dendroceros where there are three cutting faces).
• The vegetative reproduction by death and decay of thalli is less frequent in this group
than in Hepaticopsida. However, tuber formation is frequent in this group.
• Most of the species are homothallic, but some are heterothallic (Proskauer, 1948). In
heterothallic species the sex determination is genotypic, that is, two spores of a tetrad
develop into male and two into female gametophytes.
• Anthocerotopsida and Hepaticopsida are fundamentally different in the fact that in the
former an antheridial initial is the inner daughter cell produced by periclinal division of
a superficial daughter cell of the gametophyte. This suggests that Anthocerotopsida are
derived from ancestors in which antheridia developed from superficial dorsal cells.
• In Anthoceros and some other genera of this group, the antheridial initial may divide
vertically into two or four daughter cells, each of which develops into an antheridium.
• The development of the primary antheridial cell into the antheridium proper is similar
as in Sphaerocarpales and Marchantiales.
• In Anthocerotopsida, the spermatogenesis is much like that of other bryophytes and
involves a metamorphosis of androcytes into biflagellate sperms on antherozoids.

• In Anthocerotopsida the archegonial initial functions directly as a primary archegonial
cell instead of dividing into primary archegonial cell and primary stalk cell as found in
other bryophytes.
• The first division of a zygote is vertical but cases have been found (Bhardwaj, 1950;
Pande, 1932) where the transverse division occurs.
• The amphithecium divides periclinally, where the outer layer functions as the initial layer
of the jacket and the inner layer as the archesporium.
• One unique feature of Anthocerotopsida is that cells of a capsule do not mature at the
same rate and that cells in the basal portion of a capsule remain embryonic even after
those in the apical portion are fully mature. This feature is not found in other
bryophytes.
➢ Affinities of Anthocerotopsida:
• This group exhibits similarities with green algae, Hepaticopsida (liver worts), Bryopsida
(mosses) and Psilophytales of Pteridophyta.
• (A) Features common with green algae:
The green algae (Chlorophyceae) have been considered a group from which the
bryophytes and pteridophytes are believed to have originated.
(i) Usually, each cell of gametophyte has a single large chloroplast of a definite shape.
(ii) The pyrenoids are present in the chloroplasts of the cells of gametophyte. The
presence of pyrenoids is the characteristic of cells of green algae only.
(iii) The pyrenoids of Anthocerotopsida and green algae are similar in function and form
starch grains in their peripheral region.
(iv) The outline and branching of the gametophyte are similar in both cases.
(v) The presence of biciliate or biflagellate (both flagella of whiplash type) antherozoids.
• (B) Features common with liverworts (Hepaticopsida):
Many taxonomists include Anthocerotales in Hepaticae.
(i) The gametophyte is thallus-like.
(ii) The smooth-walled rhizoids are found in the members of Anthocerotopsida as well
as in the members of Jungermanniales of Hepaticopsida.

(iii) The apical growth of thallus is similar in both.
(iv) Archesporium giving rise to spores and sterile cells in both groups. The sterile cells
with spiral bands are found in Megaceros of Anthocerotopsida which exhibit the
similarity with many members of Hepaticopsida.
(v) Differentiation of the amphithecium and endothecium by periclinal walls is similar to
that of many Hepaticae.
• (C) Features common with the Bryopsida (mosses):
(i) Presence of central columella in both groups.
(ii) Large reduction of the sporogenous tissue in both Anthocerotopsida as well as
Bryopsida groups.
(iii) Presence of functional stomata (e.g., in Funaria).
(iv) Differentiation of archesporium from the inner amphithecium as in Sphagnales. This
feature shows link between Anthocerotopsida and Bryopsida.
(v) The developmental stages of embryo are quite similar. The early divisions are very
much alike.
• (D) Features common with the Pteridophyta:
(i) The presence of sunken sex organs is common in both groups.
(ii) The presence of similar vegetative structure of the gametophyte in Anthoceros and
Fern.
(iii) The presence of highly developed sporogonium with photosynthetic tissue
indeterminate growth and functional stomata.
• The abovementioned facts support that the Anthocerotopsida are a distinct but
synthetic group of plants. It forms a connecting link with liverworts and mosses on one
hand and with pteridophytes on the other. There is also a remote connection with green
algae (Chlorophyceae). Campbell (1928) suggested, “The fact that the primary
sporogenous tissue in the Anthocerotales always arises from the amphithecium, while in
all other liverworts it is developed from the endothecium, would seem to be a radical
difference”.
• Campbell is also of opinion that the sporophyte of Anthoceros with its assimilatory
system with stomata and continued growth shows the close alliance to the independent,

rootless dichotomously branched sporophyte of the primitive Fossil Group, Psilophytales.
Mehra (1957) suggested that both Anthocerotopsida and Psilopsida arose from the
common Anthorhyniaceae stock.
Biological significance of Anthocerotopsida:
The sporophytes of Anthocerotopsida exhibit probable lines of biological progress as
follows:
(i) The presence of elaborate ventilated assimilatory system suggests the beginning of
the physiological independence of the sporophyte.
(ii) The discontinuation of continuous sporogenous tissue by the growth of sterile cells
between the spore mother cells which suggests the beginning of the formation of
sporangia.
(iii) The establishment of a well-developed sterile columella from the central
endothecium suggests the beginning of the formation of conducting system, and the
initial stage in the formation of superficial sporangia.
(iv)The presence of intercalary meristematic zone suggests the beginning of the
indeterminate and continuous growth of the sporophyte.
BRYOPSIDA – SPHAGNALES
These species are aquatic or semiaquatic and grow in dense masses or cushions in swamps,
ponds and lake margins, moist heaths and wet hill sides.
➢ ANATOMY
External Features:
Plant body is gametophytic and consists of two stages: Juvenile stage and leafy
gametophore.
Juvenile stage: It is also called protonema and is formed by the germination of the
spores. It is irregularly lobed thallus like structure and one cell in thickness. It is
attached to the substratum by multicellular rhizoids with oblique septa. From the
protonema arises the erect leafy gametophyte called the gametophore.

Leafy Gametophore:
It represents the adult form. The adult gametophyte
(gametophore) is perennial and can be differentiated into axis
or ‘stem’ and ‘leaves.
It is erect and may be a foot or more in length with a diameter
up to 1.2 mm. The stem is well branched, the branching being
usually lateral. Near the apex of the stem the branches are
short and of limited growth and are clustered together closely
to form a compact head called Comal tuft or coma. The coma
formation occurs due to the presence of very short internodes at the apex of the stem.
Lower down on the stem is borne additional elongated branches. They occur usually in
tufts of 3-8 (commonly five) in the axil of every fourth leaf on the main stem. These
branches are of two types.
(a) Divergent branches: These branches grow out laterally from the stem and extend
outward in a horizontal position.
(b) Drooping or Flaogelliforms branches: These branches grow out laterally from the
stem; droop or hang or run very close to the stem. These pendent or de-current branches
act as water conductors.

‘Leaf’:
Leaves are borne on the main stem as well as on the branches. On the stem they are
little apart while on the branches they are overlapping. Leaves are arranged in a spiral
manner with a phyllotaxy of 2/5 i.e., sixth leaf will come above the first leaf. They are
thin, small, fleshy, oblong with a broad base. The margin is entire with acute apex.
Mid rib is lacking. If seen in surface view the leaf consists of meshes composed of two
different types of cells: small living photosynthetic cells containing chlorophyll and large,
hyaline rhomboidal cells. These cells are provided with small pores. These pores are
rounded in shape and mainly concerned with intake of water.
Spiral thickenings are also present in the cells. These thickenings compensate the
absence of mechanical’ issue. The leaves on the branches are smaller in size than stem.
These leaves are compactly arranged in the imbricate fashion.
Internal Structure
Axis or ‘Stem’:
The transverse section of axis can be differentiated into 3 distinct zones:
(i) Cortex: It is the outermost region of the axis.
Its cells are small and form compact tissue. In young
axis, the cortex is only one cell thick.
(ii) Prosenchymatous region: Cortex is followed by a
cylinder of narrow, thick-walled elongated cells. It is
4-6 layered and surrounds the medulla. It gives the
mechanical support to the axis’ tissue.
(iii) Medulla or Axial Cylinder: It is composed
of thin walled, colourless, parenchymatous cells. It
is like the pith of the higher plants and functions as
storage region.

‘Leaf’:
Transverse section (T.S.) of leaf shows that it is one cell thick. In young leaves the cells are
rectangular, and are of same size.
However, in mature leaves the T.S. appears as beaded or moniliform due to the presence of
two types of cells large, hyaline or capillary cells and the small, green assimilatory or
Photosynthetic cells., The two kind of cells regularly alternate with each other.
➢ REPRODUCTION
Vegetative Reproduction:
1. Innovation: It is the common method of reproduction. It takes place by the
formation of special vegetative branches known as innovations. Occasionally one
of the branches in the axillary cluster become robust and grows upwards. This
branch shows all the characteristics of main axis and known as innovation. Each
innovation develops into a new plant when detach from the parent plant.
2. Multiplication of Protonemal Branches: Any marginal cell of the primary protonema
may become meristematic and forms a green cellular filament. In apical portion
grows into flat, thallus-like green secondary protonema. Marginal cells of
secondary protonema form the leafy gametophore.
3. Regeneration: The growth of new tissues or organs to replace those lost or
damaged in injury is known as regeneration. Sphagnum has great power of
regeneration. During desiccation, the growth of the Sphagnum is checked because
the physiological activities like respiration and photosynthesis are suspended, but
the cytoplasm shows a high degree of resistance to desiccation. When water is
available these activities are resumed and normal growth of the plant takes place.
Such plants are known as pallacuophytes
Sexual Reproduction
The Antheridium:
The antheridia or the male sex organs develop on the catkin like short lateral
branches known as the antheridial or male branches. These branches develop near

the apex of the main shoot of the plant. These branches bear the leaves which are
just like the foliage leaves but in comparison they are shorter.
A mature antheridium consists a long stalk and a globular body. The stalk may be as
long as the body of the antheridium. It consists of the two to four rows of cells which
are 8-10 cells in length. The antheridial body is covered by a single layered sterile
jacket which encloses many androcytes. Each androcyte metamorphosis into a spirally
coiled biflagellate antherozoid. When the antheridium is mature, the apical cells of
the jacket absorb water, swell and undergo irregular separations which turn
backwards. The antherozoids are liberated and swim in water.

The Archegonium:
One to five archegonia develop at the tip of the short archegonial branches. The
leaves of the archegonial branches are green and much larger than the vegetative
branches. These leaves are called perichaetium. These leaves protect the archegonia,
young sporophytes and provide food to the developing sporophytes.
The archegonia which develop directly from the apical cell of the archegonial branch
are known as the primary archegonia while the remaining one are known as secondary
archegonia. A nature archegonium is long and stalked structure possessing venter and
a long neck enclosing 8 or 9 neck canal cells, a venter canal cell and an egg cell.
Fertilization:
The process of fertilization is identical with other bryophytes. Water is essential
for fertilization. At the time of fertilization, the neck canal cells along with the
venter canal cell disintegrate to form a clear passage for the antherozoids. They
enter through the cover cells and reach up to the egg, but only one fuses with the
egg to form the zygote.
The Sporophyte:
The sporogonium develops from only one archegonium. The other archegonium,
however, may also persist for some time. The mature sporogonium is differentiated
into foot and capsule. Both are connected by a short, narrow neck like constriction
which represents the suppressed seta, sporogonium is elevated on a short cylindrical,
leafless stalk, the pseudopodium. The pseudopodium is gametophytic and it is formed

by the post fertilization intercalary growth of the axis of the archegonial branch.
The pseudopodium together with the basal portion of the calyptra forms a sac-like
structure, the vaginula which encloses the foot. The main functions of the
pseudopodium are to elevate the capsule for above the perichaetial leaves, to
compensate the suppression of seta and to help in the dispersal of spores.
Foot: It is bulbous and made up of parenchymatous cells. The main function is to
absorb the food material for the developing sporophyte.
Capsule: It is spherical and dark brown in colour. It contains central columella which
is over arched by a done shaped spore sac containing haploid spores. The wall of the
capsule is 4-6 layers thick. The outer layer of the capsule wall is called epidermis.
The cells of the epidermis are compactly arranged and contain chloroplasts. It has
many non-functional and rudimentary stomata. In young sporogonium, a circular,
convex disc is present at the top of the capsule. It is called operculum. It is separated
from the rest of the capsule region by a circular (ring like) groove of thin-walled cells
called annulus.

BRYOPSIDA – ANDREALES
Andreaea is a genus of rock mosses described by Johann Hedwig in 1801.
They are small, delicate acrocarpous mosses (meaning that the capsules are formed at the
tips of vertical branches) that form dark brown or reddish cushions on wet siliceous rocks in
mountainous areas. The capsule lacks the peristome teeth and operculum of other mosses, and
opens by splitting along 4 vertical slits, the four valves remaining joined at the base and apex.
The capsule of Andreaea has no seta, but the sporophyte instead is supported by
a pseudopodium derived from gametophyte tissue, as in Sphagnum and the columella is
enclosed within the sporangium. The spores germinate to give thalloid protonemata.
➢ ANATOMY
The appearance of Andreaea rupestris is dark in colour, varying from dark
red/brown/green to black depending on its life stage. It grows in patches of dense,
cushion-like tufts up to 2–3 cm high and has imbricate leaves in dry conditions. In moist
conditions, the leaves may be falcate-secund (curved to one side) yet this does not
always hold true. Unlike some other mosses, A. rupestris have biseriate rhizoids which
aid in attaching the gametophyte to substrate.
Gametophyte
The gametophyte leaves have an ovate base tapering to a blunt to acute apex and are
less than 1mm in length. They lack a costa and may have papillae on the dorsal side,
particularly on the upper leaves of the stem. The leaves are bordered by shorter,
rhombic marginal cells and their laminal cells have thickened cell walls. Their perichaetial
leaves are typically larger than their stem leaves. In contrast to most bryophytes which
have a filamentous protonemal stage, Andreaea rupestris have thalloid protonema that
give rise to the leafy shoot of the gametophyte.
Sporophyte
As characterized by the Andreaeopsida, Andreaea rupestris have small sporophytes
which lack both an operculum and a seta. Instead of a seta, they have a pseudopodium
derived from gametophytic tissue attached to the sporangium, extending from the
perichaetium attached by a structure called the foot. Once fully mature, the sporangium
will open along 4 vertical lines of dehiscence to release the spores inside. The sporangium
is hygroscopic as it will dehisce in dry conditions to release spores from the gaps, and

will close back up in moist conditions. The spores are red-brown in colour, usually larger
than 20 μm in diameter, and lack elaters.
➢ REPRODUCTION
The sporophyte and gametophyte represent two generations of A. rupestris, also known
as the alternation of heteromorphic generations. The gametophyte stage starts with the
haploid spore, which then germinates into a thalloid protonema. The protonema then
gives rise to the leafy gametophyte which houses the male and female organs also known
as the antheridia and archegonia, respectively.
Andreaea rupestris are autoicous, meaning that their male and female organs exist on
separate branches within the same gametophyte. The close proximity of the antheridia
and archegonia helps facilitate fertilization. The antheridia contain sperm that travel
down the neck of an archegonium, which houses the egg, to fertilize it. When the egg is
fertilized and becomes a diploid zygote, it then develops into the diploid sporangium.
Note that the sporangium is attached to a haploid pseudopodium that was derived from
gametophytic tissue. Through the process of meiosis, haploid spores are produced and
released through the gaps of the dehisced sporangium.
BRYOPSIDA – FUNARIALES
Characteristic features:
• The plant body is gametophytic. Each gametophore contains rhizoids (‘stem’, and ‘leaves.
• Each gametophore has a slim, straight appearance and reaches a height of approximately
1 to 3 cm.
• The tufts are the base of the “stem” and the source of the rhizoids.
• Every rhizoid has a multicellular, branched, filamentous and multicellular structure.
• Young Rhizoids are colourless, but they turn brown when they reach adulthood.
• If Rhizoids are present on an exposed axis of the plant, they develop chlorophyll.

• The functions of rhizoids include absorption and fixation.
• The ‘Stem’ (or axis) is thin, erect and covered by the “leaves”.
• Apical tufts are spirally arranged in the 3/8 types phyllotaxy on the ‘axis.
• Each leaf is sessile and ovate, with an entire margin and an acute apex. Each leaf contains
a midrib.
• The lowermost leaves in a mature gametophore are membranous, small and called scaly;
the middle larger, greener leaves are called foliage leaves. And the uppermost, most
compactly arranged leaves, are called perichaetial.
➢ ANATOMY
External Features: The height of the erect gametophytic plants is approximately one
inch. There is an erect stem or leafy axis attached to the substratum via rhizoids. Radial
axis, sometimes branched axillary and extra-axillary. The axis is covered in spirally
arranged leaves that are closer to the apex, forming a rosette.
Eight leaves are actually arranged in three complete spirals, forming 3/8 of phyllotaxy.
This corresponds to the three cutting faces that were used when they were young. The
leaves are simple, straight, sessile and ovate with a pointed apex and smooth margins.
They attach to the stem via a broad base. While mature leaves have midribs, younger
leaves lack them.
The strong, multicellular, multi-branched rhizoids have strong systems. They have
oblique septa. The young rhizoids, which are colorless, turn brown or black as they
mature. When exposed to sunlight, the branches of rhizoids produce chloroplasts. They
are “absorbing and anchoring organs.”
Internal Features:
1. Stem:
The mature stem’s transverse section shows three distinct regions: the outer epidermis
and middle cortex.

• Epidermis: It is the outermost layer in the stem. The epidermal cells are free of pores
and stomata, and contain chloroplasts.
• Cortex: It is located between the epidermis & the central cylinder. It is multi-layered
and contains large parenchymatous cell. When young, the cortex cells contain
chloroplasts but these are lost as the stem ages. The cortical cells in a young stem look
the same, but the cortex’s outer cells become thicker and more reddish brown as it
matures. In the cortex, there are also isolated areas of cells in the peripheral area that
represent the leaf traces. These traces are not connected to the central cylinder
because they have blind ends.
• Central Cylinder: It is made up of colourless, long-walled cells that are thin-walled and
have thin walls. These cells are dead and may not contain protoplasm.
2. Leaf
The transverse section (T. S.) of the ‘leaf shows a clearly defined midrib and two lateral
wings. The ‘leaf is made up of a single layer of parenchymatous, polygonal cells. Many
prominent and large chloroplasts are found in these cells. The thick walls of cells in the
central portion of the mid-rib have a narrow conducting strand. This helps with conduction.
➢ REPRODUCTION
Reproduces through vegetative and sexual methods.
1. Vegetative Reproduction
These are the methods that make it possible:

a. By multiplication of primary protonema
Funaria spores form a multicellular, branched structure upon germination. This is called
primary protonema. Intercalary divisions create certain colourless separation cells.
These cells die and split the protonema into many-celled fragments. These fragments
become new protonemata that bear buds. Each bud becomes a leafy gametophore.
b. By secondary protonema
Secondary protonema occurs when protonema is created by other methods than the
germination spore. It can be formed from any part of the gametophyte that is not spore-
germinated, such as the ‘stem’ or ‘leaves, antheridium and archegonium paraphysis. It
develops into a leafy gametophore similar to primary protonema.
c. By Gemmae
Unfavourable conditions cause the terminal cells of protonemal branches to divide by
transverse and longitudinal divisions, forming green multicellular bodies with 10-30 cells.
These cells are known as gemmae. Gemmae turn slightly reddish brown when they reach
maturity. Gemmae will germinate new plants when they are exposed to favourable
conditions.
d. By Bulbils
These structures, which look like gemmae, are created on the rhizoids within the
substratum. They are called bulbils. These structures are not able to develop into leafy
individuals, but they lack chloroplasts.
e. Apospory:
Apospory is the process of developing gametophyte out of sporophyte, without the
formation of any spores. The sporophyte’s vegetative cells may develop green protonemal
filaments that bear lateral buds. These buds eventually become leafy gametophores.
These gametophores are called diploid. The formation of tetraploid (4n), zygote results
from sexual reproduction in these gametophores. Because they are incapable of
producing spores, sporophytes derived from tetraploid are considered sterile.
2. Sexual Reproduction in Funaria
Oogamous reproduction is the preferred method of sexual reproduction. Antheridium is
the name of male reproductive structure, while archegonium is the name for female.
Funaria is monoecious, with male and female sex organs sharing the same thallus. It can
also be autoicous (antheridia or archegonia grow on different branches of the same

branch). Leafy gametophores are found in terminal clusters and sex organs are borne
from these leafy gametophores.
The main shoot of the leafy tree tophore bears antheridia, and acts as a male branch.
The female branch is a lateral branch that grows from the male branch’s base and bears
archegonia. It is taller than the male branch. Funaria is protandrous, meaning that
archegonia mature before funaria. It allows cross fertilization.
Male Branch or Antheridiophore
L. S. of the male branch’s longitudinal section shows that its apex has an expanded and
convex shape. In different stages of development, it bears a large number of orange or
reddish-brown antheridia. The perigonial leaves are a rosette that surrounds the
projected antheridia.
Perigonium is the antheridial cluster that surrounds perigonial leaves. Paraphyses are a
large group of sterile hairs that look like clubs and are found in the antheridia.
Paraphyses are water-storing structures that protect developing antheridia and aid in
photosynthesis as well as dehiscence.
Structure of an Antheridium
Antheridium has a club-shaped shape. It can be divided into two parts:
(a) Short multicellular stalk
(b) Body of antheridium
The body of antheridium is a single-layered, sterile jacket made of flattened polyhedral
cells. The jacket’s cells contain chloroplasts, which at maturity turn orange-reddish
brown. The jacket contains a lot of androcytes, which are mother cells from an
antherozoid mothers.
The antheridium’s distal end bears one to two thick-walled, colourless cells known as
operculum at maturity. The opercular cells are mucilaginous and absorb water. They swell
and break down connections with neighbouring cells, and create a narrow pore. Through
this pore, androcytes emerge as a viscous liquid.

Development of Antheridium
An antheridium cell is a single, slightly projecting cell. It is also known as the antheridial
first. It is located at the apex the male branch. It divides through a transverse division,
forming a basal and outer cell. The embedded portion of the stalk is formed by the basal
cell. The entire antheridium is formed by the outer cell, also known as the antheridial
mom cell. It divides through transverse divisions, forming a short filament of 2-3 cell.
The stalk of antheridium is made up of lower cells. A terminal cell of the filament is
divided by two vertical intersecting walls. This differentiates an apical cell with two
cutting faces.
Segments are cut in the apical cells in two rows, in an alternate order. This method leaves
5-7 segments. The apical cells are simultaneously dividing. Meanwhile, the third and
fourth segments below the Apical Cells start dividing starting at the base by diagonal
vertical walls.
The segment is divided by the first wall into two equal-sized cells. The jacket initial is a
small cell. A larger cell divides periclinally to form an inner large primary, oogonial and
outer jacket initial. A transverse section (T. S.), shows a triangular primary androgonial
cells. This type of division occurs in all upper segments, except for the operculum-
forming apical cells.

Anticlinal divisions are the only way to divide all jacket initials and form one layered wall
made of antheridium. Primary androgonial cells split and re-divide to create the
androcyte mom cells. The cells of the final cell generation are known as androcyte
mother cells.
Each androcyte mother cells divides further to form two androcytes. Each androcyte
can produce one spermatozoid, antherozoid, or biflagellate egg. Each antherozoid has a
spirally coiled and bi-flagellated structure.
Female Branch or Archegoniphore
From the base of the male branches, the female branch grows. L. S. of the female branch
shows that paraphyses and archegonia are interwoven at its apex. Paraphyses’ terminal
cells are not swollen. A group of green leaves ‘leaves’ surrounds the archegonia cluster.
Perichaetium is the name given to the archegonial cluster and its surrounding
perichaetial foliage.
Structure of an Archegonium
The mature archegonium has a flask-shaped structure. It is attached to the female
branch by an enormous stalk. It has a long, elongated neck and a basal globular portion
called venter.
The neck is slightly tubular and twisty, single-layered, and contains six vertical rows
neck cells. These cells enclose an abaxial row of 10 or more neck canal cells. Venter wall
is two-layered and contains egg cell and venter canal cells. The venter canal cell is located
just below the neck cells.

Development of Archegonium
Archegonium is a result of a single supracellular cell, the archegonial initial. It divides
at the apex, or female branch. The archegonial initial divides through transverse division
to form the stalk cell or basal cell, and a terminal.
The stalk of the archegonium is formed by the basal cell. It divides and re-divides. The
archegonial mother cells function as the terminal cell. It is divided by three intersecting
walls, forming three peripheral cells that surround a tetrahedral-axial cell. The
peripheral cells split anticlinally to form one layered venter wall, which becomes later
two layered.
The axial cell splits transversely to create an outer primary cover and inner central cells.
The outer primary cover cell acts as an apical cell, with three lateral and one base cutting
faces. It trims three lateral segments as well as one basal segment. Each lateral segment
is divided by a vertical wall, so that six rows of cells make up the neck of archegonium.
Each basal cell contributes to the neck canal cell.
Transverse division of the inner central cell results in a transverse division that creates
an outer primary neck cell and an inner primary venter cell. Transverse divisions are
performed on the primary neck canal cell to create a row of neck cells. The lower and
middle neck canal cells are derived primarily from the primary neck cell, while the upper
neck cells are derived mainly from the primary cover cells. Transverse division is used
to create the primary venter cell and the egg cell.

Fertilization
Fertilization requires water. Antheridium’s opercular cells rupture, releasing large
amounts of antherozoids. The neck canal cells and ventral canal cells of archegonium
mature to make a mucilaginous mixture. It absorbs water and swells, pushing the cover
cells apart. This mucilaginous substance consists mainly of sugars and chemical
substances.
The neck’s cover cells separate from one another and create a passage that leads to the
egg. The splash cup is made up of rosette-shaped perigonial leaves. Rain drops fall on the
archegonial cluster at lower levels to disperse antherozoids.
Although many antherozoids may enter the archegonial neck through chemical response,
only one fuses with the egg to create the zygote. Within 10 hours, the union of male and
female nuclei occurs. Fertilization is the end of the gametophytic stage.
Sporophytic Phase
Zygote is a cell that forms the first phase of the
sporophytic cycle. The venter of an archegonium is
where sporophyte develops.
Structure of Sporophyte
Semi-parasitic, the sporophyte’s mature form can be
divided into seta, foot, and capsule.
• Foot: This is the basal part of the sporogonium.
It is a small, conical, dagger-like structure that is
embedded at the apex female branch. It acts as an
anchoring and absorption organ.
• Seta: This is a long, slim, stalk-like hygroscopic
structure. It bears its capsule at the tip. It lifts the
capsule from the leafy gametophore’s apex. Its
internal structure is similar to the axis. The epidermis
surrounds the axial cylindrical with thick walls. It
serves a mechanical function and conducts water and
nutrients to the developing capsule.

• Capsule: Capsule is the final
part of the sporophyte. It is
located at the apex the seta.
It is usually green when it is
young, but becomes bright
orange as it matures. It is
protected by a calyptra-like
cap. The archegonium’s upper
portion is where gametophytic
tissue grows.
Internal Structure of the Capsule
Longitudinal Section The capsule can be distinguished into three distinct regions:
apophasis (theca), operculum and longitudinal Section (L.S.).
a. Apophysis
It is the base sterile portion of the capsule. It is bound by the single-layered epidermis,
which is broken by stomata. The guard cells of the stomata are shaped like a single ring.
Below the epidermis, there is spongy parenchyma. The central portion of the apophysis
consists of long, thin-walled cells that form a conducting strand. It is also known as the
neck of capsule. It connects seta and capsule.
b. Theca
It is located in the middle of the capsule, where the spore-bearing region is slightly
bent. It is located between the operculum and apophysis.
Longitudinal section (L. S.) passing through the theca shows the following regions:
• Epidermis: The epidermis is the outermost layer. It can be single-layered or multi-
layered, with or without stomata.

• Hypodermis: The hypodermis is located below the epidermis. It is composed of two to
three layers, each containing colourless cells that are compactly arranged.
• Spongy parenchyma: Spongy parenchyma is made up of two to three layers containing
loosely organized chlorophyllous cells. It can be found between the hypodermis and
innermost layer. These cells can produce their own food, but are dependent on
gametophyte to obtain water and minerals. The sporophyte is therefore partially
dependent upon gametophyte.
• Air spaces: These are located just below the spongy parenchyma, and outside the
spores. Green cells (chlorenchymatous cell) traverse these air spaces. Trabecular
(elongated parenchymatous cell) is another name for them.
• Spore sac: These are located below the air spaces on each side of the columella. It has
a U-shaped shape and is broken at its base. It separates its two arms. It has an outer
wall of 3-4 cells thickness and an inner wall of one cell. The cavity of the spores is located
between the inner wall and outer wall. The cavity of the spore capsule is full of spore
mother cells when it’s young. The spore mother cells divide through meiotic divisions at
maturity and produce many haploid spores.
• Columella: This is the central region of the Theca region. It is composed of colourless,
compactly arranged parenchymatous cells. It connects the central strand in apophysis

by being wide above and narrow below. It aids in the conduction of water as well as
mineral nutrients.
c. Operculum:
• It is located in the top region of the capsule. It has four to five layers of cells and is
dome-shaped. The epidermis, which is the thickest layer of cells, is the outermost.
Operculum can be distinguished from theca by a clearly marked constriction. Below the
constriction is a diaphragm or rim. It is made up of two to three layers radially elongated,
pitted cells.
• The annulus is located immediately above the rim and consists of five to six layers of
cells superimposed on top. The upper cells of the annulus are thick, while the two layers
below are thin. Annulus separates operculum and theca. The peristome is located below
the operculum. It is located below the edge of your diaphragm. Two rings of peristomial
teeth are made up of the peristome. Each ring contains sixteen teeth.
• They are just the cuticle strips, and not cells. The outer ring’s teeth are prominent, with
red transverse bands and thick, conspicuous teeth. However, the inner ring’s teeth are
smaller, more delicate, without transverse bands, and are colourless. A mass of thin-
walled parenchymatous cells lies between the inner and peristome teeth.
Development of Sporophyte
The zygote soon after fertilization forms a wall around itself and grows in size. It splits
along a transverse wall, forming an epibasal and hypo basal cells. The epibasal cell is divided
by two intersecting, oblique walls. It distinguishes an apical from an epibasal cell by using
two cutting faces. The hypo basal cells also differentiate an apical.
These two apical cells are responsible for the differentiation of all sporophytes. The
development of embryo sporophyte therefore is bi-apical. The epibasal apical cells develop
into capsule and the upper part of the seta, while the hypo basal cell becomes foot and the
remaining portion of the seta. Both apical cell types cut out alternate segments to form the
long, filamentous structure of young sporogonium.

Dehiscence of the Capsule
Funaria is a stegocarpous, or dehiscence-oriented moss. This is done by ‘breaking down’ the
annulus. The capsule becomes inverted as it matures due to epinasty. The annulus’ thin walls
are broken and the operculum is exposed.
Hygroscopic is the outer peristomial tooth (exostome). The inner peristomial (endostome),
which do not exhibit any hygroscopic movements, acts as a sieve and allows only a few spores
at a time. The dispersal of spores is made possible by the lengthening or shortening the outer
peristomial tooth.
The exostome’s ability to absorb water and increase in length in high humidity conditions causes
them to curve inwards. Dry weather causes the exostome teeth to lose water and bend inwards
with jerky movements. This allows for the dispersal in small amounts of spores from a capsule.
The seta develops jerky movements at maturity. The dispersal of spores is further assisted
by the seta’s twisting and swinging in dry weather.
If there is sufficient moisture, spores can germinate under favorable conditions. Endosporium
is formed as one or two germ tubes when exosporium bursts. Each germ tube has multicellular
cells and green, with oblique septa. The germ tube divides by septa and grows in length to form
primary protonema, a green algal filament-like structure.

Primary Protonema - This is the young (or juvenile) stage of the gametophyte that results
from the germination spore. It can form two types of branches. The majority of branches are
horizontal and grow on the moist soil surface. They are known as chloronemal or positive
phototrophic branches, which are thick, rich in chloroplast, and some branches are called
rhizoidal, which are non-green, thin, and have oblique septa. If exposed to sunlight, these
branches can produce chlorophyll.
➢ LIFE HISTORY

BRYOPSIDA – POLYTRICHALES
Polytrichaceae is a common family of mosses. Members of this family tend to be larger than
other mosses with a thickened central stem and a rhizome. The leaves have a midrib that
bears lamellae on the upper surface. Species in this group are dioicous. Another
characteristic that identifies them is that they have from 32 to 64 peristome teeth in
their sporangium.
➢ ANATOMY
General structure - The main plant body is gametophyte. The adult plant consists of two
parts: rhizome and upright leafy shoot.
1. Rhizome: It is horizontal portion and grows underground. It bears three rows of small
brown or colourless leaves. It also bears rhizoids. The cells are rich in protoplasm and
oil globules.
2. Upright leafy shoot: The leafy shoots are much longer. It is the most conspicuous
part of the plant. It arises from rhizome. These branches consist of central axis. These
branches bear large leaves arranged spirally.
3. Leaves: Leaves have broad bases. Leaves in the upper portion are green. But the lower
ones are brown. Each leaf has a broad. colourless sheathing leaf base and narrow distal
limb. The mid-rib forms the major part of the leaf. These leaves possess extra
photosynthetic tissue in the form of closely set vertical plates of green cells. These are
known as lamellae. Green lamellae act as additional photosynthetic tissue.
Internal structure:
Leaf: Polytrichales have complex internal structure. The mid-rib region is thick. But the
margins are only one cell thick. The lower surface is bounded by epidermis. One or two
layers of sclerenchymatous tissues are present above the epidermis. The central tissue
of leaf is composed of thin-walled parenchymatous tissues. Above this are again
sclerenchymatous cells. The upper surface is formed of a layer of large cells from which
arise numerous lamellae. This upper portion is the main photosynthetic region of the leaf.
Stem: The T.S. of stem shows three regions: medulla, cortex and epidermis. The medulla
is again differentiated into two zones: central zone and peripheral zone. The cortex
consists of thick-walled cells. The innermost layer of cortex around the conducting

Bryology - Masters First semester revision text.pdf

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