Monographs Details: Fissidens adianthoides Hedw.
Authority: Pursell, Ronald A. 2007. Fissidentaceae. Fl. Neotrop. Monogr. 101 (Published by NYBG Press)
Synonyms:Dicranum adianthoides (Hedw.) F.Weber & D.Mohr, Skitophyllum adianthoides (Hedw.) Bach.Pyl., Schistophyllum adianthoides (Hedw.) Lindb., Fissidens taxifolius var. adianthoides (Hedw.) Wahlenb. ex Huebener
Description:Species Description - Plants dark green. Steins monomorphic, to 26 mm [2.6 cm] long x 5 mm wide, frequently branched; rhi-zoids basal and axillary, 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 present. Leaves inrolled from tips, ± crispate when dry, usually imbricate, as many as 24 pairs, oblong to lanceolate, acute, to 4.6 mm long x 1 mm wide; margin crenulate to serrulate, irregularly serrate distally, elimbate; costa distinct, ending 2-3 cells below apex to percurrent, taxifolius type; dorsal lamina sometimes undulate proximally, narrowed to rounded at insertion, ending at insertion to infrequently short-decurrent; vaginant laminae of cauline leaves 1/2-3/5 leaf length, acute, slightly unequal, minor lamina ending near margin; laminal cells distinct, eguttulate, usually unistratose, infrequently irregularly bistratose, firm-walled, smooth, slightly bulging, mostly irregularly hexagonal, 11-19 µm long, 1-3 marginal rows often not as deep as inner cells, with slightly thicker walls, forming a lighter band or not, juxtacostal cells larger, mostly oblong and pellucid, vaginant laminal cells slightly larger. Dioicous (?); perigonia not seen in regional plants; perichaetia on short axillary branches, mostly in proximal half of stem. Complete sporophytes not seen in regional plants. The following description is based on North American specimens. Sporophytes one per perichaetium, orange to reddish; seta to 25 mm [2.5 cm] long; theca exserted, mostly ± inclined, ± arcuate, bilaterally symmetric, to 1.5 mm long; operculum conic, long-rostrate, to 1.5 mm long; peristome taxifolius type. Spores finely papillose, 13-22 µm diam. Calyptra cucullate, smooth, to 2.5 mm long. n = 24 (Fritsch, 1991).

Discussion:This bipolar species, widely distributed in the Northern Hemisphere, has been confused with Fissi-dens osmundioides Hedw. Indeed, reports of this latter species in South America are based on erroneously determined specimens, not only of F adianthoides but also other species. Fissidens adi-anthoides can be recognized by its larger leaves (to 4.6 mm vs. to 2 mm in F osmundioides). Moreover, F adianthoides is characterized by perichaetia terminal on short lateral branches in the proximal parts of stems and smooth rhizoids while the perichaetia of F osmundioides are terminal on main stems and the rhizoids are papillose. Fissidens adianthoides and F polypodioides have similar laminal cells, but the leaf apex of the former species is acute and irregularly serrate while the leaf apex of the latter species is denticulate and obtuse to broadly acute.
Distribution:Magellanes Chile South America| Santa Catarina Brazil South America| Santa Cruz Argentina South America|