Pteridophytes are part of a large group of plants known as tracheophytes.
Tracheophytes are plants that have a vascular system that allows water and nutrients to move throughout the plant.
4. Fragmentation of the plant body - The dichotomously branched plant body, under favourable
conditions, breaks up into a number of pieces. Each portion is capable of growing into an adult plant,
e.g., Selaginella rupestries, Lycopodium phlegmaria and L. squarrosum.
By progressive death of older part of the stem - The apical young dichotomous branches of the
mature plant body owing to the death of the other part of the stem, sever their connections from it
and behave as independent plants, e.g., Lycopodium innudatum.
Vegetative buds - In Lycopodium innudatum, the whole plant
except the apical tip of the rhizome dies during winter. But on the
return of a favourable season this tip behaves as a resting bud and
germinates into a new plant.
Leafy bulbous buds are developed in certain plants, such as
Lycopodium phlegmaria and L.phyllanthus. These develop at the
base of the main stem and get separated from it. These develop into
new sporophytic plants.
5. According to Ludwig (1911), rudiments of buds and roots develop at the nodes in Equisetum
arvense, E. limosum and E. schaffneri. Each bud is capable of regenerating into a complete plant
with aerial shoots, rhizome and nodes.
In some cases adventitious buds develop on the roots, e.g., Ophioglossom pendulum, O.
attichisoni and O. vulgatum. These when detached regenerate into new plants.
Holloway (1939), reported the occurrence of buds on gametophytes of Psilotum. These are similar
in function to the buds described earlier but differ from them in originating from a single cell.
6. Gemmae - These are multicellular structures which develop on the rhizome as is the case in
Psilotum nudum, on new stem tips in Lycopodium selago and L. lucidulum or from cortical cells of
the root, e.g., L. ramulosum.
Bulbils - Protocorm-like bulbils develop in Lycopodium cernuum, L. ramulosum and Selaginella.
These differ from the protocorm in that there is no foot. These regenerate into new plants.
Tubers – these are thick-walled spherical structures containing a reserve of food. These may develop
in Selaginella either at the end of vegetative branches forming surface-tubers as in S.chrysocaulos
are developed at the ends of filamentous modified vegetative branch forming underground tubers as
in the case with S. chrysorrhizos.
7. In case of Equisetum, the tubers may be ovoid as in E. arvense or pear-shaped, e.g., E. telmatia.
Sometimes, the tubers are formed in chains. These when detached from the parent plant, are capable
of developing into new plants.
In Marsilea hirsute tubers develop from the irregular side branches covered with imperfectly-
developed leaves, such tubers show tenacity of life and can withstand desiccation for long. On the
return of favourable conditions, each germinates to produce a new plant.
Root tubercles - Tubercles from roots develop in Lycopodium cernuum and L. ramulosum. These
when detached develop new plants directly.
By branching of the protocorm - In some cases e.g., Lycopodium laterate and L. ramulosum the
protocorm produces a number of branches. These branches are capable of developing into new
plants.