What are ferns?Describe their salient features



(a) Ferns are found in tropical regions and dry rocky places.
(b) The plant body is distinguished into (i) underground stem such as rhizome (ii) it bears roots (iii) it sends aerial shoots. Leaves of fern are of two types : simple leaves with a single vein and compound leaves with several leaflets.
© The sporophyte phase is dominant in ferns.
(d) On underside of leaflets are borne sori.
(e) Sorus is protected by indusium. The sori contains sporangia.
(f) Spores germinate into prothallus, the gametophyte.
(g) The gametophyte bears antheridia and archegonia on underside. The archegonia are at notch but the antheridia lie towards the tip between rhizoids. The antheridia bear flagellated sperms. The eggs lie at the base of the archegonia.
(h) The process of fertilization occurs when water is available for the flagellated sperms, to swim to reach the egg and the zygote is formed.
(i) First leaves appear above prothallus. The roots develop below it.
(j) The sporophyte and gametophyte tissues are distinctly different shades of green.
(k) The young sporophyte develops a root bearing rhizome from which fronds projects.