Observations on spore ultrastructure in six species ofGrimmia(Bryopsida)

Ultrastructure of the spore in four Japanese species ofPtychomitriumFürnr. (Musci)

“…5 A, B), and different degrees of specialization according to the species. G. orbicularis, G. pulvinata spores are polarised, with a thick perine cover and plastids with reduced internal membrane system (Estébanez et al 1997). Nevertheless, many sporal characters of Grimmia funalis, including symmetry, thylakoid development, and even occasional presence of irregular intine protrusions, link both genera.…”

“…Brownish colours could be related with plastid reduction, but at least in some cases it is due to the spore wall opacity (Horton, 1982;Estébanez et al 1997). Plastid reduction in mature spores has been proved only in Funaria, Sphagnum, Dawsonia, Riella (cf.…”

“…Plastid reduction in mature spores has been proved only in Funaria, Sphagnum, Dawsonia, Riella (cf. Neidhart, 1979), Ceratodon (Olesen & Mogensen, 1978) and three species of Grimmia (Estébanez et al 1997). All of these species have a thick sporoderm.…”

“…According to Brown and Lemmon (1990), the presence of perine separates mosses from liverworts and hornworts, and both Sphagnum and Andreaea show distinctive features regarding the exine stratification, enabling each of them to be differentiated from Bryiidae. In addition, the perine elements and stratification of the intine could be useful for taxonomic purposes at the generic or specific levels (Carrió n et al 1995;Guerra et al 1991;Estébanez et al 1997). Nevertheless, moss spore ornamentation is much less conspicuous than in vascular plants and in recent years just a limited number of papers have been published on moss spores (Luizi-Ponzo & Barth, 1999;Du, Wang & Zhang, 2000).…”

“…In a previous ultrastructural study on six species of the genus Grimmia (Estébanez et al 1997) we reported a remarkable interspecific variability and some particular features, such as a multilamellar structure of the mature exine. No data on spore ultrastructure are available for the genus Ptychomitrium.…”