Pg.no. 37
The mosses has roots like stem and leaf like structure.
They have alternation of generation. (Sporophytic phase alternates with the
Gametophytic phase)
They reproduce sexually by gametes and asexually by spores, gemma and
fragmentation.
They live both on land and water so they are called amphibious cryptogams.
Uses of Bryophytes:
Peat moss or sphagnum in dried condition is used as fuel.
Sphagnum is also used as antiseptic and absorbent bandage in the hospitals.
Sphagnum is also used as seed bed in green houses.
Bryophytes control soil erosion as they form a carpet over the soil.
Pteridophytes:
The first successful group of cryptogams’ to live on the land with a vascular system is
Pteridophytes. They are called Vascular Cryptogams (xylem and phloem are present to
conduct water and food). These plants are living since the Jurassic period.
Uses of Pteriodophytes:
Grown as ornamental plants for their beautiful fronds.
Marselia is used as food.
Leaves vary in nature.
Lycopodium power is used as mechine.
Gymnosperms:
Plant body is differentiated into root, stem and leaf.
Well developed top root system.
Leaves vary in nature.
Gymnosperms undergo secondary thickening.
They have two phases in its life cycle. Sporophytic and Gametophytic phase.
Most of the Gymnosperms produce male and female cons.
The leaves are dimorphic (two types of leaves) in selaginella.
Stem is a rhizome. They are seedless true land plants.
They reproduce by means of spores.
Spores may be hormosporous of heterospourous.
Saporophyte alternates with the gametophyte.