Weissia controversa Hedw.
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Authority
Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part One: Sphagnales to Bryales. Mem. New York Bot. Gard. 69 (1): 1-452.
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Family
Pottiaceae
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Scientific Name
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Description
Species Description - Plants small, green above, light-brown below, generally about 2 mm high. Leaves 1.5-2.5 mm long, narrowly long-lanceolate to oblong-lanceolate, sharply acute, mucronate, not much differentiated at base; margins incurved to tightly involute; costa with epidermal cells quadrate and papillose on the ventral surface, elongate and papillose on the dorsal; upper cells in longitudinal rows, subquadrate to hexagonal, 7-9 µm wide, bulging and bearing 4-6 bifid papillae on both surfaces (occasionally fused together in a capitate cluster); basal cells differentiated across the leaf, mostly thin-walled, up to 25 µm wide and 2-3:1. Autoicous. Setae 4-6 mm long, yellow-brown, twisted clockwise; capsules 1-1.4 mm long, oval, yellow- to red-brown; exothecial cells in 1—2(-4) layers, subquadrate to short-rectangular, ca. 30 p m wide and 1-3:1, rather thin-walled; annulus of 2-3 rows of cells; operculum 0.5-0.8 mm long, rostrate; peristome teeth none, few and rudimentary, or 16 oblong to long-triangular and irregularly cleft, straight, yellow to orange, papillose to low-spiculose teeth with as many as 6 joints and up to 125 µm long (occasionally falling with the operculum). Spores (15-) 18-20(-23) µm, yellow to brown, papillose.
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Discussion
Fig. 160
W. controversa Hedw., Sp. Muse. 67.1801.
W. viridula Hedw. ex Brid., Muse. Recent. Suppl. 4: 38. 1819.
Hymenostomum mexicanum Card., Rev. Bryol. 36: 70. 1909.
The peristome m a y be entirely wanting or reduced to a few yellow teeth hidden behind the annulus, or it m a y fall with the operculum. Plants lacking a peristome m a y appear to have remnants of a membrane at the mouth, as in sect. Hymenostomum. This membrane is usually present, however, in peristomate plants as well. The thinness of the capsule wall used by Andrews (1924) to separate W. controversa from W. hedwigii Crum (of sect. Hymenostomum) cannot be depended on, as Mexican specimens of W. controversa may have both thick capsule walls and peristomes. Weissia hedwigii is absent from Mexico, but a similar species, W. condensa (Voit) Lindb., is represented there. It has oblong-lanceolate leaves that are broad as compared with those of W. controversa. The type of Hymenostomum mexicanum may be considered an eperistomate example of Weissia controversa, but numerous specimens identified as H . mexicanum belong to W . condensa instead.
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Distribution
On soil, rock, walls, and bases of trees at low to moderate elevations; Baja California, Baja California Sur, Chiapas, Chihuahua, Coahuila, Distrito Federal, Hidalgo, Jalisco, Morelos, Nuevo Leon, Oaxaca, San Luis Potosi, Sonora, Tamaulipas, Veracruz.—Weedy and cosmopolitan.