DESCRIPCIÓN DEL DESARROLLO DEL GAMETOFITO Y PRIMERAS FASES DEL ESPOROFITO DE POLYSTICHUM ORDINATUM (KUNZE) LIEBM. (DRYOPTERIDACEAE-PTERIDOPHYTA)*

Abstract

This study examined the life cycle of Polystichum ordinatum (Kunze) Liebm. Specimens were collected at Cuetzalan, Puebla,
Mexico. The spores were sown according to
the technique of Montoya-Casimiro et al.
(2000). The germination pattern was of the
Vittaria type, and prothallial development
was of the Aspidium type. Two types of
gametophyte were found: cordate with only
archegonia and elongated with antheridia.
In the latter type of gametophyte antheridia
developed in four different positions: a) in
the middle part, b) in a proximal central
position, c) over the whole surface and,
d) along the margin of the gametophyte.
Trichomes were observed in cordate and
elongated gametophytes; only gametophytes
with marginal antheridia were glabrous.
Young sporophytes were obtained around
325 days after sowing. The life cycle of P.
ordinatum is like that of Equisetum, having
the same kind of spores, exosporic gametophytes and unisexual gametophytes.