- Pteridophytes are the first terrestrial plants that evolved vascular tissues like xylem and phloem. They reproduce via spores and have alternation of generations with separate sporophyte and gametophyte phases. - They are divided into four classes - Psilopsida, Lycopsida, Sphenopsida, and Pteropsida - based on characteristics of their vascular tissues, sporangia, and other structures. - Pteridophytes can have different types of steles like protosteles, siphonosteles, and others to transport water and nutrients throughout the plant.

1. General Characters of
Pteridophytes

2. Introduction
• Pteridophtes are vascular cryptogams i.e. plants of
this group produce vascular tissues i.e. xylem and
phloem for conduction of water, minerals and for
translocation of food
• Evolutionarily they are the first terrestrial plants to
possesses vascular tissues
• They are mostly herbaceous and found in cool and
shady places, though some may flourish in sandy
soil condition
Equisetum

3. General Characteristics of Pteridophyta
• The main plant body is sporophyte which is differentiated into true roots,
stem and leaves e.g. selaginella
• Leaves are small called microphylls as in selaginella or large called
macrophylls as in true ferns
• Vascular tissue is differentiated into xylem and phloem

4. • These are flowerless plants
• Sporophytes bearing sporangia that are subtended by leaf like
appendages called sporophylls
• The sporangia produce spores by meiosis in spore mother cell
• The spores germinate to produce multicellular free living,
photosynthetic thalloid gametophyte called prothallus
• They need water for fertilization and the spread of pteridophytes
is limited and restricted to narrow geographical region
General Characteristics of Pteridophyta

5. • The gametophytic plant is smaller and less differentiated
• The gametophyte bears male reproductive structures called antheridia and
female reproductive structures called archegonia
• The antheridia bear antherozoids and archegonia bear oosphere
• The plants show definite alternation of generation
• Zygote produces a multicellular well differentiated sporophyte which is the
dominant phase of the pteridophytes
General Characteristics of Pteridophyta

6. • In majority of pteridophytes all the spores are of similar kinds, such plants are
called homosporous
• Some pteridophytes produce two types of spores mega and micro and are
called heterosporous
• Megaspores and microspores germinate and give rise to female and male
gametophytes respectively e.g. Selaginella and Salvinia
General Characteristics of Pteridophyta

7. Pteridophytes has been divided into following classes:
• Psilopsida
• Lycopsida
• Sphenopsida
• Pteropsida

8. PSILOPSIDA
• Vascular tissue is present only in stem
• Rhizoids are present for absorption of water
and minerals
• Leaves usually absent
• Sporangia terminal and homosporous
• Many plants are extinct, only four species
are living e.g. Psilotum

9. • Club mosses and spike mosses
Plants divided into stem, leaves and roots
• Vascular tissue is found in all organs of the
plants
• Leaves are small and thin
• Most plants bear a group of sporophylls at the
apices of branches which is called cone or
strobilus
• Some plants are homosporous like Lycopodium
others are heterosporous like Selaginella
LYCOPSIDA

10. • This includes plants with very small leaves which
are arranged in whorls on nodes
• There are ridges and grooves on the stem
• Always homosporous e.g. Equisetum
SPHENOPSIDA
Equisetum

11. • This includes plants with fan-shaped leaves
• Plant body highly developed, stem usually rhizome
• In some ferns stem is erect and may go up to 15ft
• Sporangia are born on lower surface, either in the
middle or on the margins of sporophylls
• They may be homosporous e.g. Dryopteris, Pteris,
Adiantum or heterosporous e.g. Marsilea
• Spores germinate to produce gametophytes
bearing antheridia and archegonia
PTEROPSIDA

12. • The stele is the fundamental unit of vascular system i.e. present in root or
stem
• The stele consists of the vascular tissues, pericycle and the pith
• The innermost layer of cortex is endodermis and pericycle is the outermost
layer of the stele
• In pteridophytes following kinds of stele is recognized:
 Protostele
 Siphonostele
Stelar System in Pteridophytes

13. Protostele
• It is the simplest and most primitive type of stele in which the vascular tissues
form a central solid mass of xylem surrounded by phloem. Pith is absent
• Protosteles are of following types:
Haplostele
It is the small core of xylem surrounded by a uniform layer of phloem e.g.
Rhynia which is fossil plant and Selaginella kraussiana
Actinostele
It has a xylem core with radiating arms. In actinostele phloem is present
in the form of separate patches alternating with radiating arms of xylem e.g.
Lycopodium serratum

14. Plectostele
In this stele xylem occurs in the form of small parallel bands alternating
with phloem plates e.g. Lycopodium clavatum
Mixed protostele with phloem
In this stele xylem groups are scattered in the form of irregular patches
that are embedded in the ground mass of phloem e.g. Lycopodium cernuum
Mixed protostele with parenchyma
In this stele xylem groups are scattered in the form of irregular patches
that are embedded in the ground mass of parenchyma e.g.
Hymenophyllum demissum

16.  Siphonostele
• In the siphonostele the centrally placed xylem core is replaced by
parenchymatous cells and therefore central parenchymatous pith surrounded
by xylem is present in the siphonostele.
• It is of two types
Ectophloic siphonostele
In this stele xylem is in the form of hollow cylinder surrounding a pith
with the phloem occurring only outside the xylem e.g. Schizaea, Osmunda
Amphiphloic siphonostele
the xylem form a hollow cylinder enclosing the pith with the xylem
occurring both on the inner and outer side of the xylem e.g. Adiantum, Marsilea

18. • Siphonostele classified on the basis of leaf gaps.They are of two kinds:
Solenostele
Siphonostele which are perforated by scattered leaf gaps are known as
solenostele.
They are of two types:
• Ectophloic solenostele
• Amphiphloic solenostele

19. Dictyostele
In many Filicophyta leaves are
inserted on the stem in close succession.
In such cases leaf gaps overlap thus the
vascular cylinder of stem appears
dissected into meristeles separated from
one another by parenchymatous tissue or
leaf gaps
These meristeles appear arranged
in a ring. Such a stele is known as
dissected siphonostele or dictyostele.
e.g. Dryopteris fillix-max

20. Other type of stele
• Polycycle stele
The vascular tissue is present in the form of two or more concentric
cylinders e.g. Pteridium aquilinum. Polycyclic steles may be polycyclic
solenosteles or polycyclic dictyosteles.
• Polystele
Sometimes more than one steles are present in the axis of some
Pteridophytes e.g. Selaginella kraussiana , S.laevigata