Robert R. Ireland
Plagiothecium subg. Taxiphyllum (M. Fleischer) A. J. Grout
Plants medium- to large-sized, in thin to dense mats, complanate-foliate, sometimes julaceous or subjulaceous, glossy, light- to dark-green or yellow-green. Stems creeping, simple or sparingly and irregularly branched, cortical cells small, thick-walled, central strand sometimes present; rhizoids smooth, in clusters below leaf insertions usually on ventral surface of stems; axillary hairs with 1--2(--3) short brown basal cells and a single elongate apical cell; pseudoparaphyllia large to small, foliose. Stem and branch leaves similar, stiff to flaccid, crowded and imbricate to distant, erect to wide-spreading or squarrose, often complanate, rarely secund at the tips, smooth or occasionally plicate, plane to concave, symmetric or nearly so, nondecurrent, ovate, ovate-lanceolate, oblong-lanceolate, oblong-ovate or linear-oblong, acute to subobtuse, sometimes acuminate; margins plane or recurved, serrate to serrulate above leaf middle, serrulate to entire below; costa short and double, sometimes lacking; cells moderately thick-walled, linear-flexuose, rhomboidal near leaf apex, smooth or prorate at distal ends on abaxial leaf surface, with walls not pitted; alar regions distinctly differentiated with 1 to several rows of quadrate to rectangular cells, or undifferentiated or nearly so. Specialized asexual reproduction lacking. Sexual condition dioicous or rarely synoicous, usually sterile. Perigonia and perichaetia at base of stems and branches, perigonial bracts small, ovate, perichaetial bracts lanceolate to ovate, slenderly acuminate, ± spreading from an erect base, margins plane. Seta smooth, elongate, straight or somewhat flexuose, dark red to brown. Capsule inclined to cernuous, straight to subarcuate, yellowish brown to reddish brown, smooth, oblong-ovoid, somewhat contracted below mouth and wrinkled at neck when dry; opercula obliquely rostrate, often shorter than urn; annulus present, persistent, of 2 rows of cells; peristome cross-striolate below, papillose distally, bordered, trabeculate; endostome with a high to low basal membrane, keeled segments and cilia shorter than or approximately the same length as the segments, in groups of 1--3. Calyptra cucullate, smooth, naked. Spores globose to ovoid, smooth to minutely papillose, 7--28 µm.
Species10--15 (4 in the flora): terrestrial habitats, primarily on calcareous substrates, temperate, subtropical or tropical regions; North, Central and South America, West Indies, Europe, Asia, Africa, Australia.
SELECTED REFERENCES
Crum, H. A. and L. E. Anderson. 1981. Mosses of Eastern North America. Vol. 2. New York. Ireland, R. R. 1982. Moss Flora of the Maritime Provinces. National Museums of Canada, Natl. Mus. Nat. Sciences, Publs. in Botany, No. 13. Ottawa. Ireland, R. R. 1969. A taxonomic revision of the genus Plagiothecium for North America, north of Mexico. National Museums of Canada, Natl. Mus. Nat. Sciences, Publs.in Botany 1: 1--118. Ireland, R. R. 1986. Synopsis of the genus Taxiphyllum for North America. Lindbergia 12: 153--157. Iwatsuki, Z. 1963. Bryological Miscellanies XII. Preliminary notes on the Japanese species of Taxiphyllum and its related genera. J. Hattori Bot. Lab. 26: 63--69.
OTHER REFERENCES
Ireland, R. R. 1994. Taxiphyllum. In: A. J. Sharp, H. Crum and P. M. Eckel(eds.), The Moss Flora of Mexico, Part 2. Orthotrichales to Polytrichales. Mem. New York Bot. Gard. 69: 1022--1025.
Mishler, B. D. & N. G. Miller. 1983. Distributional studies of Massachusetts bryophytes. Rhodora 85: 421--432.
Reese, W. D. 1984. Mosses of the Gulf South. Baton Rouge.
