Background and Aims:

Pellaea (Pteridaceae) is a fern genus with a subcosmopolitan distribution. The spore morphology and gametophytic development of several species of this taxon have been studied and the presence of apogamy has been characteristically registered. The aim of this work was to describe and compare the prothallial development of eight species of Pellaea sect. Pellaea from Mexico.

Methods:

Voucher specimens were collected for each species, as well as fertile pinnae from which spores were obtained, which were then sowed in Petri dishes with agar and Thompson's medium. Cultures were maintained at a temperature of 18-25 °C, with a 12 h light/dark photoperiod, from the start of germination until the gametophyte maturity.

Key results:

All taxa had trilete spores and showed Vittaria-type germination. Two types of prothallial development were observed: Adiantum and Ceratopteris. The shape of the adult gametophytes was cordate, spatulate-cordate or cordate-reniform; the margins were smooth, undulate or with two tooth-shaped cells. The sporophytes of P. notabilis, P. ribae, P. sagittata, P. ternifolia and P. villosa were of sexual origin, whereas those of P. cordifolia and P. oaxacana were apogamous. Pellaea sagittata and P. ternifolia developed sporophytes of both sexual and apogamous origins. Pellaea pringlei and a specimen of P. cordifolia did not produce sporophytes.

Conclusions:

The development and characteristics of the gametophytes studied were similar to those reported in other studies, obtaining in most species sporophytes of sexual and/or apogamous origin. For the first time, the prothallic development of P. oaxacana, P. ribae and P. villosa is described, providing information for 15 of the 16 species of Pellaea sect. Pellaea occurring in Mexico.

        · resumo em Espanhol     · texto em Espanhol     · Espanhol ( pdf )