Sexual phase morphogenesis in the fern Arachniodes denticulata (Dryopteridaceae)

Spore morphology and sexual fase development of Arachniodes denticulata (Sw .) Ching are described from material collected in states of Hidalgo, Oaxaca and Veracruz, Mexico tone sample from each locality). The spores were sown in Thompson medium with agar (30 Petri dishes). The spores are monolete, w ith perine, ellipsoid in shape and non chlorophyllic. The germination is Vi ttaria-type and the prothallial development Aspidium-type; the gametophytes are cordiform-spatulate to cordiform-reniform in shape, with unicellular c apitate trichome in margin and surface; rhizoids without chloroplasts; game tangia are the common type in leptosporangiate homosporous ferns. No sporop hytes were observed after 200 days of culture. It is concluded that A. dent iculata share common characteristics with A. aristata, A. assamica and spec ies of the genera Cyrtomium, Dryopteris and Polystichum, such as type of sp ore germination, prothallial development and, in early stages of prothallia l growth formation of trichomes. Didymochlaena truncatula differ from those species in prothallial development Adiantum-type and naked prothalli.