Zelometeorium

• Authority

  Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.

• Family

  Meteoriaceae

• Scientific Name

  Zelometeorium

• Description

  Genus Description - Plants medium-sized, in green to golden, pendent masses. Stems pendent to creeping, irregularly to pinnately branched, flagellate branches sometimes present; in cross-section with small thick-walled cells surrounding larger thin-walled cells, central strand small, of small cells; pseudoparaphyllia broadly foliose; axillary hairs with a single short-rectangular brown basal cell and 2-3 elongate hyaline distal cells. Stem and branch leaves differentiated, the stem leaves ± auriculate and strongly clasping the stem, longer and more slenderly acuminate, the branch leaves spreading to squarrose-recurved from a somewhat clasping base, all leaves inserted in a U-shaped line, lanceolate-ovate to suborbicular, apiculate to piliferous; margins subentire to sharply serrulate, plane throughout or revolute below; costa single, slender, ending near or somewhat above midleaf, sometimes projecting as a small spine at apex; cells long-hexagonal to linear-flexuose, smooth, firm-walled, sometimes ± porose, becoming distinctly porose toward the insertion and shorter in a few rows; alar cells somewhat to well differentiated, subquadrate to short-rectangular, firm-walled, not or somewhat porose. Asexual propagula rarely present, of flagellate branches. Dioicous. Perichaetia conspicuous, on pendent branches; leaves loosely convolute, oblong-lanceolate, abruptly to gradually long-acuminate, concave; margins serrulate above, entire below, plane; costa single or absent; cells linear, smooth, firm-walled, porose. Setae relatively short, slightly roughened (or smooth?), reddish; capsules short-exserted, erect, long-cylindric; exothecial cells quadrate to rectangular, thick-walled, not collenchymatous; annulus differentiated; operculum conic-rostrate; peristome inserted below the mouth, pale, exostome teeth linear-triangular, on the front surface papillose throughout, more densely so above, not trabeculate at back, unornamented; endostome with a low basal membrane, segments keeled, perforate, ca. as long as the teeth, cilia none or short and single. Spores spherical, smooth or roughened. Calyptrae mitrate, lobed at base, erect-pilose, roughened above.

• Discussion

  Zelometeorium Manuel, J. Hattori Bot. Lab. 43: 110. 1977. Meteorium sect. Squarridium Müll. Hal., Linnaea 42: 492. 1879, nom. nud. Discussion. Zelometeorium is characterized by pendent plants with leaves, especially those of the stems, strongly clasping or sheathing and often acuminate. There is a single, slender costa and the leaf cells are elongate and smooth. The alar cells are more or less differentiated and even on a single stem some leaves have better developed alar cells than other leaves. Sporophytes are rare but provide justification for generic recognition. The exostome teeth are inserted well below the mouth and are papillose on the front surface; the calyptra is mitrate and hairy. Zelometeorium is much like the Old World Meteoriopsis, in which it was included, because of clasping leaves but differs in the smooth leaf cells and papillose exostome teeth. Meteoridium differs in the more widely spaced, nonclasping leaves, striate exostome teeth, and cucullate calyptrae. Zelometeorium was revised by Manuel (1977b). In the West Indies we have a single, albeit variable, species.