36. Chenia R. H. Zander, Phytologia. 65: 424. 1989.
[For Chen Pan Chieh, 1907-1970, Chinese bryologist]
Richard H. Zander
Phascum sect. Leptophascum Müller Hal., Flora 71: 7. 1888; Phascum subg. Leptophascum (Müller Hal.) G. Roth
Plants forming a low turf, green distally, brownish proximally. Stems short to elongate, to 3 mm; hyalodermis absent, sclerodermis present, central strand weak to strong; axillary hairs small, of 3-4 cells, proximal cell firm-walled. Leaves appressed and contorted when dry, spreading when moist; ligulate to elliptic, adaxial surface occasionally grooved along costa, plane or broadly channeled across leaf. 1.5-2.5 mm; base rectangular or not differentiated in shape; margins distally plane, weakly recurved or plane basally, irregularly denticulate distally with sharp, mid cell projections ending in a simple papilla, marginal cells often smaller; apex rounded to broadly acute, occasionally sharply apiculate; costa weak, ending several (6-9) cells before the apex or percurrent, lamina inserted adaxially to laterally, adaxial cells short-rectangular, narrower than laminal cells, in 2 rows, abaxial cells short-rectangular; transverse section rounded to elliptic, adaxial epidermis present, adaxial stereid band absent, guide cells 2 in 1 layers, hydroid strand present, small to large, abaxial stereid band very weak or occasionally absent, rounded in sectional shape, abaxial epidermis present; proximal cells differentiated across the leaf base except for one or more rows of marginal cells, rectangular; distal medial cells large, (15-)20-25(-30) µm wide, 1:1, bulging-hexagonal, 1-stratose; papillae absent (distal marginal teeth may be interpreted as sharp papillae), cell walls thin, weakly trigonous, convex on both sides. Specialized asexual reproduction by brood bodies that are sometimes present on rhizoids in soil. Sexual condition dioicous. [Seta ca. 1.2 cm. Capsule stegocarpous or cleistocarpous; theca ovate; annulus of 2-3 layers of strongly vesiculose cells, persistent; peristome teeth when present 16, filamentous, somewhat anastomosing, straight or weakly twisted counterclockwise. Calyptra cucullate. Spores ca. 10 µm.] KOH laminal color reaction red.
Species 3 (1 in the flora): North America, Mexico, South America, Europe, e Asia, Australia.
Chenia includes both cleistocarpous and peristomate taxa. The diagnostic characters are leaves ligulate to spathulate, sharply crenulate to irregularly dentate above with sharp mid-marginal wall projections, often sharply apiculate by a distinctive thick-walled cell or cells, distal laminal cells large, weakly trigonous, epapillose, and red in KOH solution.
Neumann, A. J. 1972. Observations on the morphology and biology of the moss Tortula vectensis E. Warb. & Crundw. in Louisiana. Bryologist 75: 580-583. Reese, W. D. 1967. The discovery of Tortula vectensis in North America. Bryologist 70: 112-114.