In which one of the following , male and female gametohphytes do not have free living independent existence?

Options

A. Pteris
B. Funaria
C. Polytrichum
D. Cedrus

Answer

A

Explanation

(a) In Pteris (also Dryopteris) the spore germinates to produce the prothallus. The prothallus is a small, green flat, surface loving, thallus-like object. It is monoecious and bears sex organs on the ventral side. The aantheridia (male sex organs) arise amongthe rhizoida towards the posterior side of the prothallus and are emergent. The archegonia develop in central cushion behind the apical notch. In these plants male and female, gametophytes do have free living independent existence. All species of Polytrichum are dioecious. The antheridia and archegonia are borne on different gametophore. The plant body is an erect leafy shoot but is not the entire gametophyte. The leafy shoot arise from protonema (the juvenile stage). The leafy gametophore of Funaria reproduces sexually by formation of antheridia and archegonia. The antheridia are formed at the summit of a relatively small, thin, leafy shoot, which develops first. The female branch arises later as a lateral outgrowth from the base of parent male shoot. Cedrus is a gymnosperm in which main plant body is a sporophyte on which reduced type of gametophytes are formed.