Monographs Details: Fissidens beckettii Mitt.
Synonyms:Fissidens quisqueyanus Pursell, Fissidens jaliscensis Pursell
Description:Species Description - Plants light green. Stems dimorphic, unbranched, 2.5 mm x l.5 mm wide; rhizoids basal, smooth, reddish; axillary hyaline nodules absent; epidermis and outer tier of cortical cells small, incrassate, pigmented; inner cortical cells larger, thin-walled, hyaline; central strand absent. Leaves ± crispate when dry, imbricate, as many as 5 pairs, lanceolate, acute, to 1 mm long x 0.3 mm wide, perichaetial leaves longest; margin ± entire, sometimes serrulate distally, limbate on all laminae, limbidium unistratose, indistinct, reaching apex in larger leaves, confluent with costa; costa percurrent to short-excurrent, bryoides type; dorsal lamina narrowed proximally, ending at insertion or somewhat above; vaginant laminae 1/2-2/3 leaf length, unequal, minor lamina of all leaves narrowed distally, ending on or near costa; laminal cells distinct, eguttulate, unistratose, firm-walled, smooth, plane to slightly bulging, rhombic to hexagonal, 14-32 pm x 7-12 pm wide. Monoicous (rhizautoicous); perigonial stems gemmiform, clustered around base of perichaetial stems. Sporophytes 1 per perichaetium, yellow, darkening with age; seta smooth, 3.0-5.5 mm long; theca exserted, inclined to horizontal, ± bilaterally symmetric, 0.3-0.6 mm long, stomatose, exothecial cells quadrate to oblong, collenchymatous; peristome bryoides type; operculum conic, short-rostrate, to 0.3 mm long. Spores smooth, 11-14 pm diam. Calyptra cucullate, smooth, 0.4 mm long.
Discussion:Synonyms from outside the area of this study (Iwatsuki and Suzuki, 1982, 1989): Fissidens burmensis E. B. Bartram, Fissidens curvato-xiphioides Dixon & P. de la Varde, and Fissidens mouensis Thér.Fissidens beckettii is very much like Fissidens curvatus; both species have dimorphic stems, similar laminal cells and a limbidium that is confluent at the apex of well developed leaves. However, in F. beckettii the minor lamina narrows toward the costa and ends on or near the costa in all leaves. In F. curvatus the vaginant laminae end near or at the leaf margin except in perichaetial leaves.
Distrito Federal Mexico North America
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