Monographs Details: Fissidens bourgaeanus Besch.
Authority: Pursell, Ronald A. 2007. Fissidentaceae. Fl. Neotrop. Monogr. 101 (Published by NYBG Press)
Family:Fissidentaceae
Synonyms:Fissidens austro-adianthoides Müll.Hal., Fissidens incrassato-limbatus Cardot
Description:Species Description - Plants dark green. Stems monomorphic, to 65 mm [6.5 cm] long x 10 mm [1 cm] wide, unbranched and branched; rhizoids basal, smooth, reddish; axillary hyaline nodules absent; epidermis and outer 1-2 tiers of cortical cells small, incrassate, usually pigmented; inner cortical cells larger, hyaline; central strand present. Leaves ± crispate when dry, imbricate, as many as 57 pairs, lanceolate to oblong-lanceolate, undulate, acute to short-acuminate, 3.4-6.2 mm long x 0.5-1.3 mm wide; margin ± entire to irregularly dentate, particularly at apex, ± entire to irregularly or regularly serrulate on vaginant laminae, elimbate; costa distinct, ± percurrent, taxifolius type; dorsal lamina truncate-rounded at insertion, not decurrent; vaginant laminae of cauline leaves 1/2— 3/5 leaf length, acute, equal to slightly unequal, minor lamina ending on the margin or near the margin; laminal cells distinct, eguttulate, mostly unis-tratose, infrequently irregularly bistratose in dorsal and ventral laminae, firm-walled, smooth, slightly bulging, rounded to irregularly hexagonal, 8-15 µm long, juxtacostal cells larger, 2-5 marginal rows thicker, forming a dark band. Dioicous; perigonia unknown; perichaetia terminal on short axillary branches. Sporophytes, spores, and calyptra unknown.

Discussion:Fissidens bourgaeanus is a rather large and coarse plant that can be confused with F. polypodi-oides, F. dubius, and F. taxifolius. The leaves of F. bourgaeanus, however, are acute to acute-acuminate while in F. polypodioides the leaves are obtuse to broadly acute. Moreover, the leaves of F. bourgaeanus are easily broken when dry, but those of F polypodioides seldom fracture. The marginal laminal cells of F bourgaeanus are usually thicker thans those of F polypodioides and form a dark marginal band. Nevertheless, in some Honduran plants, i.e., Allen 12646 (MO), the marginal laminai cells are not as thick as in most specimens and are lighter. These plants can be mistaken for F dubius, but plants of this species are smaller (to 25 mm long x 3.5 mm wide) and the laminal cells are smaller (7-10 µm long). Fissidens bourgaeanus is easily distinguished from F. taxifolius by the absence of mammillose cells on the vaginant laminae.

The closest relative of Fissidens bourgaeanus is an endemic of the Hawaiian Islands, F pacificus Ângstr. Only female plants are known in both species (Pursell & Hoe, 1977). Both species also have leaves in which the margin varies from more or less entire to strongly dentate, a percurrent costa, a central strand, and laminal cells that are infrequently irregularly bistratose and similar in size and shape. The leaves of F. bourgaeanus, however, are larger than those F. pacificus (a maximum length of 6.2 vs. a maximum length of 5 mm). The 2-5 rows of marginal laminal cells in F bourgaeanus are much thicker than the other laminal cells, forming a dark band, but in F pacificus the marginal laminal cells (up to 8 rows) are only slightly thicker than the interior laminai cells, forming a faintly lighter band rather than a darker band.
Distribution:Puebla Mexico North America| San Luis Potosí Mexico North America| Alta Verapaz Guatemala Central America| Huehuetenango Guatemala Central America| Quiché Guatemala Central America| Olancho Honduras Central America| Santa Bárbara Honduras Central America| Jamaica South America| Independencia Dominican Republic South America|