Diphyscium C. Mohr, Obs. Bot. 34. 1803.
* [Greek, di-physkion, two little guts, i.e., a little sac within a sac]
Authors: W. B. Schofield
Plants gregarious, forming compact short turf. Leaves lingulate, costate, 1--2-stratose, distal cells chlorophyllose, quadrate to isodiametric, thick-walled and papillose or mammillose or smooth, the proximal cells rectangular, hyaline and smooth. Perigonial leaves similar to vegetative leaves, except that the interior are reduced and enclose paraphyses, axillary hairs and elongate antheridia. Perichaetial leaves long-awned with awn smooth or spinulose, the awn often longer than the lamina, with the laminal apex lacerate and ciliate, when without sporangium strongly imbricate and penicellate, enclosing paraphyses, axillary hairs and a few archegonia. Calyptra conic, barely covering operculum.
Species 12 (2 in the flora): this is the most widespread genus of the family---mainly temperate to subtropical in North and northern South America, Europe, Asia, Atlantic Islands (Azores, Madeira), Pacific Islands, Australia.
This genus is sufficiently distinctive that it is unlikely to be confused with any other in North America if perichaetia or sporophytes are present. Vegetative material is superficially similar to that of the Pottiaceae, especially in leaf form and papillosity. Fortunately perichaetia and sporophytes are frequent in the genus' eastern range, while the turf firmly cemented by rhizoids is a trait not shared by Pottiaceae in the same range.
SELECTED REFERENCES
Harvill, A. M. 1950. Diphyscium cumberlandianum, a pre-Pliocene relic with palaeotropical affinities. Bryologiest 53: 277--282. Magombo, Z. L. K. 2003. Taxonomic revision of the moss family Diphysciaceae M. Fleisch. (Musci). J. Hattori Bot. Lab. 94: 1-86. Shaw, J., L. E. Anderson and B. D. Mishler. 1987. Peristome development in mosses in relation to systematics and evolution. I. Diphyscium foliosum (Buxbaumiaceae). Mem. N.Y. Bot. Garden 45: 55--70.
