Homomallium sharpii Ando & Higuchi 1983

Homomallium sharpii

Homomallium sharpii Ando & Higuchi, Bryologist 86: 374. 1983 [1984]. Type: Mexico. Tamaulipas: La Perra (El Porvenir), Rancho del Cielo above Gómez Farias, 6300 ft, Sharp 5641a (holotype: TENN!; isotypes: HIRO, MICH!).

Plants medium-sized, in flat mats, shiny, soft, yellow-green to yellow-brown. Stems to 4 cm long, creeping, elongate, irregularly pinnately branched; branches erect-ascending, somewhat curved, to 1 cm long; stems in cross section with 2–4 rows of small, thick-walled cells surrounding abruptly larger firm-walled cells, central strand of small, very thin-walled cells; pseudoparaphyllia filamentous; axillary hairs of 1 short brown basal cell and 1 elongate hyaline apical cell. Stem and branch leaves somewhat differentiated; stem leaves 0.9–1.1 × 0.4–0.6 mm, ± homomallous, ± falcate, concave, broadly ovate-lanceolate, long-acuminate; branch leaves not homomallous, 1–1.3 × 0.3–0.5 mm, ovate-lanceolate, long-acuminate; margins subentire to serrulate above, entire below, usually erect above, plane below; costa short and double; cells long-hexagonal, flexuose, (30–)40–60 μm long at midleaf, mostly 3–5 μm wide, as short as 25 μm long in the acumen, smooth; alar cells subquadrate to oblate (especially along the margins) in 6–8 rows, extending up the margins by 8–13 cells. Perichaetial leaves erect, oblong-lanceolate, convolute, gradually narrow-acuminate; margins subentire. Setae 1–1.8 cm long, reddish; capsules 1.3–2 mm long, suberect to inclined, cylindrical; annulus of 1 row of thick-walled cells; operculum ˜0.4 mm long, mostly conic-apiculate; exostome teeth cross-striolate below, coarsely papillose above, trabeculate at back; endostome yellowish, papillose throughout, with a high basal membrane, segments keeled, perforate, cilia in groups of 2–3. Spores 13–15 μm in diameter. Calyptrae cucullate, naked, smooth.

Distribution and ecology: Northeast Mexico; endemic; growing on limestone, at 1900–2500 m.

Illustrations in publications: Fig. 756 in Ando (1994: 1018).

Discussion: This species differs from H. mexicanum in the nonhomomallous branch leaves with longer acumina and fewer alar cells. The stem and branch leaves are differentiated much more so than in H. mexicanum. The spores are smaller and the peristomial cilia are in groups of 2–3.

Specimens examined: MEXICO. San Luis Potosí: Just E of San Francisco, 45 km E of San Luis Potosí, at Km 218 along Hwy. 70, 2166 m, Magill 2591a, 2593 (HIRO, TENN); on hillsides along Hwy. 70 near Km 226, 37 km E of San Luis Potosí, 2318 m, Magill 2577 (HIRO, TENN). Tamaulipas: Only the type seen.

Homomallium sharpii là một loài Rêu trong họ Hypnaceae. Loài này được Ando & Higuchi mô tả khoa học đầu tiên năm 1983.