Monographs Details: Fissidens yanoae Pursell
Description:Species Description - Plants light green. Stems monomorphic, unbranched and branched, to 6 mm long x 35 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 somewhat crispate when dry, as many as 10 pairs, lanceolate, acute, often apiculate or cuspidate, to 3 mm long x 0.5 mm wide, perichaetial leaves longest; margin crenulate-serrulate, ± entire in proximal parts of vaginant laminae of perichaetial leaves, elimbate; costa ending 2-3 cells below leaf apex or percurrent to short-excurrent, bryoides type; dorsal lamina narrowed to insertion or ending slightly above insertion, not decurrent; vaginant laminae of cauline leaves ± 1/2 leaf length, acute, ± equal, minor lamina ending 1/2 or less the distance between costa and margin; laminal cells distinct, eguttulate, unistratose, firm-walled, mammillose, irregularly quadrate to hexagonal, 8-11 µm long, somewhat larger and smooth in proximal parts of vaginant laminae. Monoicous (gonioautoicous); perigonia gemmiform, axillary; perichaetia terminal on stems and branches. Sporophytes 1-2 per perichaetium, yellow, darkening with age; seta smooth, to 0.2 mm long; theca immersed, erect, radially symmetric to ± arcuate, bilaterally symmetric, to 1.0 mm long, stomatose, exothecial cells quadrate to oblong, vertical walls thicker than horizontal walls; peristome anomalous, teeth erect when wet, undivided to imperfectly divided, dorsal trabeculae sharply papillose, dorsal lamellae ± smooth proximally, upper parts 1/2 spirally thickened; operculum conic, short-rostrate, 0.3 mm long. Spores not seen. Calyptra cucullate, smooth, 0.3 mm long.
Discussion:Fissidens yanoae is closest to F. lagenarius; both species share similar laminai cells and both have anomalous peristomes. However, the leaves of F. yanoae are elimbate, whereas those of F lagenarius are limbate on the proximal halves of the vaginant laminae of perichaetial and subtending leaves. Moreover, the capsule of F. lagenarius is exserted above the undifferentiated perichaetial leaves, but the capsules of F. yanoae are immersed in the much longer perichaetial leaves.
Distribution:Brazil South America