1. BIO 210- Cryptogams:
Bryophytes and Pteridopytes
Acquatic (Algae) to Terrestrial habitat (land
plants)
• Hypothesis in Botany that all plants evolved from a
common ancestor, ancient green algae.
What account for this hypothesis?
• Modern green algae share many biochemical and
metabolic traits with modern plants as ff:
• -Green algae and plants contain chlorophyll a and b and
accessory pigments, xanthophylls (yellow pigments) and
carotenes (orange pigments) and carry out
photosynthesis
2. Con’d
• -Both have cellulose as major component of
cell wall
• -Stores excess carbohydrates as starch,
• -Plants and some green algae form cell plate
during cytokinesis in mitotic cell division
• Ultrastructural and molecular data on DNA
and RNA sequences provide evidence that
plants may have descended from a group of
ancient green algae called charophytes.
3. Bryophytes
• Bryophytes are early living nonvascular plants which
include the mosses, liverworts and hornworts.
• May have evolved from green algae
Characteristics
• They lack vascular tissues, true roots, stem and leaves.
• Have cuticle; multicellular gametangia; stomata
(Advancements over algae)
• Habitat - Require moist environment; some are tolerant
of dry areas (need moisture for active growth and sexual
reproduction)
• Exhibits alternation of generations: Gametophyte is
haploid but dominant and conspicuous, sporophyte is
diploid and dependent on the gametophyte.
4. • Dioicous bryophytes produce only
antheridia (sperm producing structures)
or archegonia (egg producing structures)
on a single plant body.
• Monoicous/autoicous bryophytes
produce both antheridia and archegonia
on the same plant body.
5. The Linnaeus system of Classification
Kingdom
Division
Class
Order
Family
Genus
Species
7. Characteristics of Hepaticopsida:
• The liverworts grow usually in moist, shady habitats
such as banks of streams, marshy ground, damp soil,
bark of trees and on wood logs.
• The plant body of a liverwort is thalloid or made of
thalli (sing. thallus) which show dichotomous
branching
• Eg., Marchantia: The thallus is dorsoventrally flattened
and closely appressed to the substrate.
• The thallus shows differentiation into two layers: an
upper photosynthetic or assimilatory region and a
lower storage region with a well defined epidermis
bearing air channels.
8. Cont’d
• It has tiny cup like structures called gemmae cups
bearing gemmae which are used for asexual
reproduction.
• Multicellular purple colored scales and unicellular
rhizoids are present on the ventral surface of the
thallus.
• Antheridia and archegonia are present on special
erect gametophores called antheridiophores and
archegoniophores respectively born on separate
thalli. Hence they are heterothallic
12. Reproduction
• Asexual reproduction in liverworts takes place
by:
1 Fragmentation of thalli,
2. Gemmae (sing. gemma).
Gemmae are green, multicellular, asexual buds,
which develop in small receptacles called
gemma cups located on the thalli. The gemmae
become detached from the parent body and
germinate under favourable condition.
13. Sexual reproduction
• During sexual reproduction, male and female
sex organs are produced on different thalli.
The sporophyte is differentiated into a foot,
seta and capsule. After meiosis, spores are
produced within the capsule. These haploid
spores germinate to form free-living
gametophytes (male/female)
• Male gametophyte bears antheridium which
produces flagellated sperms/antherizoids
14. Cont’d
• The female gametophyte bears archegonium
which produces eggs
• The sperm cell swims in a film of water into
the archegonium to fertilize the egg which
develops into a zygote
• The zygote develops into embryo
• The embryo develops into sporophyte which
contain the sporogenous cells that undergo
meiosis to produce the spores.
17. Class: Anthocerotopsida
(hornworts)
• Habitat: live in disturbed habitats eg fallow fields
and roadsides
• X’tics: Presence of a single large chloroplast in each
cell resembles certain algal cells than plant cells. In
contrast, mosses, liverworts and other plants have
many disk-shaped chloroplast per cell.
• -In the common hornwort, Anthoceros natans, the
archegonia and antheridia are embedded in the
thallus/ gametophyte rather than on
archegoniophores and antheridiophores
18. Cont’d
• -After fertilization and development, a needle-
like sporophyte emerged out of the
gametophyte thallus, forming a spike or
”horn” and hence the name hornwort
• -A single gametophyte often produces
multiple sporophytes
• -Meiosis occurs to produce spores in each
sporangium.
• -Sporangium split open from the top to
release spores
19. Cont’d
• Each spore germinate to give rise to a new
gametophyte
• In hornworts the sporophyte continue to grow
from their bases attached to gametophyte
(indeterminate) unlike mosses and liverworts
(determinate).
The life cycle is the same as that of
Hepaticopsida
Assignment: Write short notes on life cycle of
the Anthocerotopsida
22. Class: Bryopsida/Musci (Mosses)
• Gametophytes
• The gametophyte generation is dominant.
• Gametophytes of mosses have green "leafy shoots" and
multicellular rhizoids (structures that resemble roots).
• The rhizoids- anchorage, absorption of water and mineral
nutrients.
• They possess stomata and cuticle (adaptations to live on
land).
• They lack vascular tissues, hence no true roots, stems, or
leaves.
• Gametophytes may grow either erect or flat on the ground.
• Their size is restricted by lack of vascular tissue. Some species
of moss have water-conducting cells and sugar-conducting
cells but lack lignin
23. Cont’d
• The gametophyte often bears gametangia at the top of
the plant. Many mosses have separate sexes; male plant
that bears the antheridia and a female plant that bears
the archegonia. Other mosses produce antheridia and
archegonium on the same plant.
• The archegonia produce eggs, and antheridia produce
antherizoids/motile sperm.
• The sterile layer that comprises the outer part of
archegonia and antheridia helps protect the delicate
gametes by preventing them from drying out.
• The unprotected motile sperm must swim in a film of
water or splash by rain droplets from the antheridium to
the archegonium which secrets chemicals to attract and
guide the sperm to fuse with the egg to form a diploid
zygote
24. Cont’d
– Sporophyte
• The zygote formed in the archegonium after
fertilization grows by mitosis into a multicellular
embryo.
• A sporophyte develops from an embryo which is still
enclosed in the archegonium of the female
gametophyte plant.
• The sporophyte is permanently attached to the
gametophyte and nutritionally depend on it.
• The mature sporophyte consists of a foot which
anchores the sporophyte to the gametophyte and
absorbs minerals and nutrient from it, a seta/stalk, and
a capsule which contains sporocytes/sporogenous
cells/spore mother cells
25.
26. Cont’d
• The sporogenous cells/sporocytes within
the sporophyte undergo meiosis to
produce a single kind of haploid
spore(homosporous). If a spore lands in a
suitable place, it germinates into a
protonema, the initial filamentous stage
of a gametophyte plant.
• The protonema form buds each of which
grows into a green gametophyte and the
life cycle continues.
28. Importance of mosses
– Food for mammals, birds
– Important in soil formation and reduction of soil erosion,
particularly along stream banks
– Commercial moss- peat moss (Sphagnum) multiplied in
moss bioreactors are developed as a new tool to
monitor air pollution.
• Fuel (dried).
• Soil conditioner- helps retain moisture.
• Also used by florists to hold moisture.
• They also store large amount of carbon which helps to reduce
global warming or greenhouse effect
29. Characteristics of Pteridophytes
• Members of this group are most primitive living
vascular plant. No Seed formation.
• Pteridophytes are mostly terrestrial sometimes
growing in the moist, cool and shady places eg
Selaginella sp, Lycopodium sp, Equisetum sp,
Nephrolepis sp, Dryopteris sp etc. Some are aquatic
like Azolla sp and Salvinia sp.
• Pteridophytes shows large variation in form, size and
habit. It ranges from the small annuals to the large
tree like perennial forms.
30. Characteristics of Peridophytes
cont’d
• The plant body is differentiated into root,
stem and leaves.
• The prominent plant body is the sporophyte
and represents the dominant phase in the life
cycle. The sporophyte is nutritionally
independent of the gametophyte.
• Plants are either homosporous (eg.)
Equisetum, Lycopodium, Pterium, Nephrolepis
or heterosporous (eg. Selaginella, Marsilea,
Salvinia).
31. Characteristics of Peridophytes
cont’d
• The leaves vary from the simplest form to the
compound nature. On the basis of the nature
of leaves the pteridophytes are classified into:
i. Microphyllous pteridophytes,
ii. Macrophyllous pteridophytes.
• The stem is usually branched; branching is
monopodial or dichotomous.
• The leaves and stem possess filliform
trichomes. Stomata are present on both the
upper and lower surface of the leaf.
32. Characteristics of Pteridophytes
cont’d.
• The young leaves are coiled in nature- crosier
or fiddlehead.
• It possesses underground horizontally growing
stems called rhizomes.
• The stele is a protostele (Lycopodium,
Selaginella) Siphonostele (Equisetum,
Ophioglossum pendulum) dictyostele (Pteris,
Nephrolepis) or polycyclic (Angiopteris).
33. Characteristics of Peridophytes
cont’d
• The root and stem possess a well-developed vascular
system having the xylem and phloem. The cambial
ring is absent so the secondary growth does not
occurs.
• The leaves bearing sporangia are known as
sporophylls.
• In the heterosporous plants, the sporophylls with
megasporangia are called megasporophyll and with
microsporangia are called microsporophyll.
• Asexual reproduction is by spores produced in the
sporangia, fragmentation and budding also occur
34. Characteristics of Peridophytes
cont’d
• The sporangia are borne on the ventral surface of the
leaves. In one member, Ophioglossum a fertile spike is
present.
• The embryo of pteridophytes is classified into exoscopic
embryo and endoscopic embryo.
• Life cycle of pteridophytes is diplobiontic. It exhibits
heteromorphic alternation between the gametophytic and
sporophytic generation. That is morphologically distinct
sporophytic and gametophytic generation.
35. Characteristics of Pteridophytes
Cont’d
• In heterosporous species; the microspores
give rise to the male gametophyte and
megaspore give rise to the female
gametophyte.
• In the homosporous pteridophytes antheridia
and the archegonia are borne on same
prothallus.
• Water is essential for fertilization.
• Presence of protective jacket cells in the sex
organs.
36. Four classes of Kingdom
Pteridophyta:
• 1. Psilotopsida (Psilotum);
• 2. Lycopsida (Selaginella, Lycopodium; the
club mosses),
• 3. Equisitopsida/Sphenopsida (Equisetum,
horse tails) and
• 4. Filicopsida/Pteropsida (The Ferns eg
Nephrolepis, Dryopteris, Pteris, Adiantum=
Terrestrial
Marselia, Azolla, Salvinia = Aquatics).
38. Class: Psilotopsida
eg. Psilotum (whisk fern)
• Family Psilotaceae, order Psilotales, and class
Psilotopsida . The name of the genus is from
Greek psilos = naked, because it lacks organs,
such as leaves and roots normally found in
other ferns.
• Psilotum- dichotomous branching, terminal
sporangia and a lack of roots but are anchored
by creeping rhizomes.
• Has vascular tissue
39. Cont’d
• Psilotum nadum has vertical stem that exhibits
dichotomous branching and horizontal
underground rhizome. Upright stem of
Psilotum are green and carry out
photosynthesis.
• The gametophyte is non-photosynthetic due
to its subterranean location. It is nourished
symbiotically by mycorrhizal fungi
• Antherozoids are spirally coiled and multi-
flagellated.
40.
41. Class: Lycopsida
• The sporophyte plant body is differentiated into
definite root, stem and leaves.
• The sporophytes are dichotomously branched.
• The leaves are usually small thus microphyllous.
• The xylem in stem exarch.
• Sporangia are borne singly on the adaxial (upper)
surface of the sporophylls.
• The spores may be of either one type i.e.,
homosporous (e.g., Lycopodium) or two types i.e.,
heterosporous (e.g., Selaginella).
• The spores develop into independent gametophyte.
44. Class: Equisitopsida/Sphenopsida
• Stems and branches are jointed with nodes and internodes.
The internodes have longitudinal ridges and furrows.
• The leaves are extremely reduced and borne in whorls at the
nodes of aerial branches and stems.
• Branches arise in whorls.
• The sporangia develop on appendage called sporangiophore.
Sporangial walls are thick.
• Most of the members are homosporous including Equisetum.
However, some extinct forms were heterosporous (e.g.,
Catamites casheana).
• The gametophytes are exosporic (free-living, develop outside
spore walls) and green.
• 7. Antherozoids are multiflagellated.
• 8. The embryo is without suspensor and is exoscopic
45. Class: Filicopsida/Pteropsida
• The sporophytes are usually perennial in nature and
differentiated into roots, stem and spirally arranged
leaves.
• 2. Most of the members grow in moist and shaded
habitats, either epiphytic or terrestrial. A few are
aquatics.
• 3. Mostly, the rhizomes are short and stout.
• 4. The leaves are large (megasporophylls), pinnately
compound and described as frond, except
Ophioglossum (simple leaf).
• 5. The rachis is covered with brown hairs (ramenta).
46. Con’d.
• 6. Young fronds show circinate vernation (coiling of
leaves), except Ophioglossum.
• 7. The stele in Pteropsida shows a wide variety of
types, e.g., protostele, siphonostele,
• solenostele, dictyostele and polycyclic stele.
• 8. Most ferns are homosporous, but a few aquatic
members are heterosporous.
• 9. Sporangia are borne at the tips or at the margin of
the pinnule or to the abaxial surface of the fronds.
Phyllosporous- sporangia are born on the leaf.
Stachyosporous- sporangia are born in the axil
of the leaf.
47. Classification Ferns
Kingdom: Plantae
Subkingdom: Tracheobionta
Division: Pteridophyta
Class: Filicopsida
The are 4 orders:
Order: Hydropteridales
Order : Marattiales
Order : Ophioglossales
Order : Polypodiales
48. Cont’d
Order: Hydropteridales
Family: Azollaceae – Azolla family,
Genus: Azolla
Family Marsileaceae – Water-clover family
Genus: Maesilea
Species: ancyclopoda
Family: Salviniaceae – Floating Fern family
Genus: Salvinia
Species: natan
49. Classification of Angiopteris evecta
Kingdom Plantae
Subkingdom Tracheobionta
Division Pteridophyta
Class Filicopsida
Order Marattiales
Family Marattiaceae
Genus Angiopteris
Species evecta
50. Classification of Botrychium
virginianum
Kingdom Plantae
Subkingdom Tracheobionta
Division Pteridophyta
Class Filicopsida
Order Ophioglossales
Family Ophioglossaceae
Genus Botrychium
Species: virginianum
51. Classification of Nephrolepis biserrata
Kingdom Plantae
Subkingdom Tracheobionta
Division Pteridophyta
Class Filicopsida
Order Polypodiales
Family Dryopteridaceae
Genus Nephrolepis
Species: biserrata
