Monographs Details: Anomodon
Authority: Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
Description:Genus Description - Plants medium-sized to fairly robust, in stiff, dull, dark-green, sometimes glaucous, or yellow-brown, lax or dense mats. Stems creeping, slender, sparsely radiculose, without primary and secondary stem differentiation, branches arising laterally from creeping stems, irregularly but densely branched, the branches ± ascending, simple or branched, often slender or tapered; in cross-section with small thick-walled cells surrounding larger firm-walled cells, central strand present or absent; paraphyllia none; pseudoparaphyllia none or ± foliose; axillary hairs with 1-3 short brown or hyaline basal cells and 1-3 elongate hyaline distal cells. Stem and branch leaves similar or differentiated, stem leaves ± abruptly long-acuminate, somewhat broader than branch leaves; branch leaves ± erect when dry, sometimes ± contorted, rapidly ± wide-spreading when moist, lingulate to lanceolate from a broad, oblong to ovate base, rounded-obtuse to acuminate-piliferous, mostly broadly decurrent; margins subentire except for projecting marginal papillae, plane or revolute; costa single, yellow, sometimes flexuose, ending above midleaf but well below apex; cells small, subquadrate to hexagonal, densely pluripapillose almost to base, rarely (extralimitally) unipapillose to smooth, ± thin-walled; alar cells poorly differentiated, at least in branch leaves, but cells between alar region and costa oblong, smooth, thick-walled. Asexual propagula none. Dioicous. Perichaetial leaves ± erect, apices spreading when dry, sheathing at base, oblong-lanceolate, sometimes broadly so, broadly to narrowly acuminate; margins entire to serrulate above, plane; costa none; cells rectangular to rounded-oblong, smooth, firm- to thick-walled; alar cells not differentiated. Setae elongate, smooth, reddish, flexuose; capsules erect and symmetric, cylindric; exothecial cells short-rectangular, firm-walled; annulus differentiated or not; operculum conic to obliquely conic-rostrate; columella cylindric, ending near midurn to exserted; peristome double, bone-white when dry, yellowish white when moist, attached at the mouth, exostome teeth narrowly triangular, not shouldered, narrowly bordered, on the front surface cross-striolate below with overlying papillae, papillose above, not or weakly trabeculate at back; endostome with a medium-high basal membrane, segments short to fairly well developed, ± keeled, not or narrowly perforate, cilia rudimentary or none. Spores spherical, finely papillose. Calyptrae cucullate, naked, smooth or rarely roughened above.
Discussion:Anomodon Hook. & Taylor, Muscol. Brit. 79. 1818; Neckera sect. Anomodon (Hook. & Taylor) Wallr. in Bluff & Fingerh., Comp. Fl. Germ. 3(Fl. Crypt. Germ. 1): 217. 1831; Hypnum sect. Theliphyllum subsect. Anomodon (Hook. & Taylor) Müll. Hal., Syn. Musc. Frond. 2: 468. 1851.
Hypnum sect. Attenuata Bals.-Criv. & De Not., Prodr. Bryol. Mediol. 96. 1834 (as nom. nud. in Syn. Muse. Mediol. 14. 1833).
Hypnum sect. Teliphylla subsect. Anomodontea T. Jensen, Bryol. Danic. 197. 1856, nom. illeg.
Discussion. Anomodon, primarily a north temperate genus, is characterized by slender branches with erect leaves that spread rapidly on moistening. The leaves vary from obtuse to slenderly acuminate but all have a yellow costa ending in the upper half of the leaf and (at least in the New World) pluripapillose cells. Although uncommonly fertile, the bone-white (when dry) exostome teeth are more or less striolate below and papillose above. The pluripapillose cells will distinguish it from Herpetineuron and Thelia. The most likely source of confusion comes from Meteorium. However, in Meteorium the leaves are always acuminate, usually more or less auriculate, with mostly longer upper cells with more discrete papillae and a large inverted V-shaped area at the leaf base with smooth cells. Also, leaves in Meteorium are only erect-spreading rather than wide-spreading when moist, and spread much more slowly than in Anomodon when moistened.
Although of limited local use since it does not include either of our two species, Iwatsuki’s (1963a) treatment of the eastern Asian species provides useful insights into the genus.