Monographs Details: Fissidens grandifrons Brid.
Authority: Pursell, Ronald A. 2007. Fissidentaceae. Fl. Neotrop. Monogr. 101 (Published by NYBG Press)
Family:Fissidentaceae
Synonyms:Skitophyllum congestum Bach.Pyl., Pachyfissidens grandifrons (Brid.) Limpr., Schistophyllum strictum Brid., Fissidens insignis Müll.Hal., Fissidens grandifrons var. strictus Besch., Fissidens strictus Hook. & Wilson, Skitophyllum strictum Paris
Description:Species Description - Plants dark green to brown-black, often encrusted with lime, coarse to the touch, typically submerged in rapidly running water. Stems monomorphic, to 100 mm [10 cm], usually profusely branched; rhizoids basal and axillary, smooth to papillose, reddish; axillary hyaline nodules present; epidermis and outer 1-2 tiers of cortical cells small, incrassate, pigmented; inner cortical cells larger, thin-walled, hyaline; central strand absent. Leaves little changed when dry, usually tightly imbricate, as many as 60 or more pairs, lanceolate, obtuse to rounded, to 4 mm long x 0.5 mm wide; margin ± entire, elimbate; costa ± obscured by small, smooth, plain to slightly bulging cells, ending a few cells below leaf apex, basically taxifolius type but variable in structure; dorsal lamina narrowed, ending at insertion to slightly decurrent; vaginant laminae of cauline leaves 1/2-2/3 leaf length, acute, equal; laminal cells distinct, eguttulate, uni- to 4-stratose at leaf margin, inner cells of dorsal and ventral laminae bi- to pluristratose, uni- to 4-stratose in vaginant laminae, firm-walled, surface cells smooth, plane to slightly bulging, irregularly quadrate to hexagonal, 7-13 µm long. Dioicous (?); perigonia not seen; perichaetia terminal on short axillary branches near middle of stem. Sporophytes not seen in Neotropical collections. The following description is based on specimens from Taiwan (Lai 8699, NY, Lin 12831, NICH) and Pakistan (Higuchi 20161, NICH): Sporophytes reddish; seta 1.3-1.9 cm long; theca exserted, slightly arcuate, bilaterally symmetric, 1.5-2 mm long, stomatose and estomatose, exothecial cells quadrate to oblong, walls evenly thickened; peristome taxifolius type. Spores finely papillose, 20-23 µm diam. Calyptra not seen. n=12, 14, 16 (Fritsch, 1991).

Discussion:Synonyms from outside the area of this study (Brugge-man-Nannenga et al. (1994): Fissidens diversiretis Broth, in Hand.-Mazz. (non Fissidens diversiretis E. B. Bartram), Fissidens planicaulis Besch., Fissidens sub grandifrons Müll. Hal., and Fissidens yunnanensis Besch.

Fissidens grandifrons, because of its aquatic habitat, and stiff, elimbate leaves in which the laminal cells are pluristratose and the costa more or less obscured, is not likely to be confused with other species in the area except F. geijskesii and F. rochensis. The leaves of F. geijskesii are similar in shape and arrangement to those of F. grandifrons, but not coarse to the touch and the costa is not obscured. Whereas the capsule of F. grandifrons is exserted on a long seta that of F. geijskesii is supported by a short seta and is immersed to emergent. Moreover, sporophytes of F. grandifrons are rare, while those of F. geijskesii are numerous. Fissidens grandifrons has a typical taxifolius type peristome, unlike the anomalous peristome of F. geijskesii. Leaves in some expressions of F. rochensis can be pluristratose, but they are limbate and the peristome is the bryoides type.

As reflected by its morphologic structure, F. grandifrons is an aquatic species that has retained a terrestrial type sporophyte (Pursell & Allen, 1994). The costa of F. grandifrons, which is often difficult to see clearly in surface view, is quite variable when viewed in transverse section. As described by Pursell and Allen (1994), the costa in the proximal parts of some leaves occasionally has a single file of ventral stereid cells. At that time the costa was interpreted to be the oblongifolius type, but upon further consideration was considered to be the taxifolius type (Pursell & Bruggeman, 2004). At times, the two dorsal stereid bands in both the proximal and distal parts of the leaf can fuse or the stereid bands in the distal part of the leaf can be lost.

Grout (1943) reported F. grandifrons from Mexico as F. diversiretis Broth, in Hand.-Mazz.

Distribution and Ecology: Mexico (Oaxaca, Sonora, Veracruz); Central America (Guatemala); attached to rocks, stones, and decaying wood, submerged in flowing streams; sea level-2800 m. This species is widespread in the United States (from Michigan and Wisconsin south to Tennessee, Alabama, Missouri, and Arkansas; from Washington south to California; and, Montana, Wyoming and Nevada); Canada (Ontario, Alberta, and British Columbia); southwestern and central Europe; temperate Asia.

Distribution:Oaxaca Mexico North America| Sonora Mexico North America| Huehuetenango Guatemala Central America| Quiché Guatemala Central America| San Marcos Guatemala Central America|