Monographs Details: Pseudo-calliergon
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 robust, sometimes turgid, in mostly lustrous, green to yellow-brown, loose tufts. Stems often erect, sometimes decumbent, unbranched to irregularly pinnate ± in a single plane; in cross-section without a hyalodermis, with small thick-walled cells surrounding larger thinner-walled cells, central strand of small thin-walled cells; paraphyllia absent; pseudoparaphyllia broadly folióse; axillary hairs with 1-2 short brown basal cells and 1-2(-3) elongate hyaline to yellowish distal cells. Stem and branch leaves somewhat differentiated, with branch leaves smaller and narrower, stem leaves large, mostly crowded, appressed to erect-spreading, ovate-lanceolate to broadly ovate, short- to long-acuminate or broadly rounded, slightly to deeply concave, not plicate, not to long-decurrent; margins entire to serrulate, plane; costa short and double to long and single, often variable within species; cells linear, smooth, thin-walled and not porose to thick-walled and porose, becoming shorter, broader, thicker-walled, and more porose toward the insertion; alar cells typically strongly differentiated, yellowish, somewhat to strongly inflated. Asexual propagula none. Dioicous. Perichaetial leaves erect, ovate, ± acuminate, plicate; margins entire or serrulate, more strongly so above, plane; costa mostly single, ending at or above midleaf; cells linear, smooth, firm- to thick-walled, not to strongly porose. Setae elongate, smooth, reddish, arising from a hairy vaginula; capsules inclined to horizontal, arcuate, asymmetric, cylindric; exothecial cells quadrate to long-rectangular, thin- to firm-walled, not collenchymatous, becoming oblate at the mouth; annulus differentiated, deciduous; operculum conic; exostome teeth yellow-brown, shouldered, strongly bordered, on the front surface typically cross-striolate below, coarsely papillose above, trabeculate at back; endostome with a high basal membrane, segments well developed to slender, keeled, not or narrowly perforate, cilia in groups of 1-4, nodose. Spores spherical, finely papillose. Calyptrae cucullate, naked, smooth.
Discussion:Pseudo-calliergon (Limpr.) Loeske, Hedwigia 46: 311. 1907; Hypnum subgen. Calliergon sect. Pseudo-Calliergon Limpr. in Rabenh., Rabenh. Krypt.-Fl., ed. 2, 4(3 [Laubm. Deutschl.]): 547. 1899, non Hypnum sect. Pseudocalliergon Renauld, Bryologist 4: 63. 1901, “Pseudocaliergori" [= Hypnum sect. Calliergidium Renauld ex Cardot & Thér. = Calliergidium (Cardot & Thér.) Grout]; Drepanocladus sect. Pseudocalliergon (Limpr.) Broth., Laubm. Fennoskand. 486. 1923.
Calliergon sect. Trifaria C. E. O. Jensen, Bot. Not. 1921: 30. 1921.
Discussion. Pseudo-calliergon is characterized by glossy plants of wet calcareous habitats, with variably costate leaves and mostly well-developed alar cells. It seems most closely related to Drepanocladus, although in aspect they are very different. The genus was monographed by Hedenäs (1990a) for northern Europe. The species of the genus were previously included in Drepanocladus and Calliergon. Our single species was previously most often recognized in Calliergon, and Karczmarz’s (1971) monograph could be consulted for more detail.