Morphology of some polystichoid ferns. I. The gametophytes of Arachniodes, Cyrtomium and Polystichum

Abstract

The morphology of the spores and prothalli of Arachniodes aristata, A. assamica, Cyrtomium caryotideum, C. falcatum and 10 species of Polystichum is described. The spores are bilateral with a smooth exine and the perine smooth in Cyrtomium and granulose to spinulose in the others. Spore germination is of the Vittaria type and prothallial development is of the Aspidium type. The adult prothallus of Arachniodes and Polystichum is cordate, with profuse papillate hairs. Sex organs are of the common leptosporangiate type. The antheridium dehisces by a pore-like opening in the cap cell in Polystichum, whereas the cap cell collapses at dehiscence in Arachniodes. Both species of Cyrtomium are apogamous; the thallus becomes irregular in shape in C. caryotideum but is cordate in C. falcatum.