EVERYDAY SCIENCE

Detailed explanation-1: -Final answer: Flagellated male gametes are present in all three Riccia, Dryopteris, and Cycas.

Detailed explanation-2: -Cycas is heterosporous. It produces two kinds of spores. It is dioecious, i.e. male and female reproductive parts are borne on different plants. The sexual reproduction is oogamous, i.e. the egg is quite large in size and non-motile compared to male gametes.

Detailed explanation-3: -Male gametes of Cycas are large, top-like, spirally twisted with cilia. In the male strobiles (cones) there are microsporophylls (fertile leaves of the strobile), that contain microsporangia. Within the microsporagium spore mother cells undergo meiosis and generate haploid microspores.

Detailed explanation-4: -Flagellated male gametes are present in Riccia, Dryopteris and Cycas. The male gametes of bryophytes are biflagellate, and those of pteridophytes are multiflagellate, except Selaginella having biflagellate gametes. The male gametes of gymnosperms are non motile except those of Cycas having multiciliate gametes.

Detailed explanation-5: -Bryophytes have muticellular male sex organs called antheridia. Antheridia produce biflagellate male gametes called antherozoids. Antherozoids are released into water in which they swim to reach the archegonium or the female sex organ.