21. Grimmia reflexidens C. Müll. 厚壁紫萼藓 hou-bi zi-e xian
Syn. Musc. Frond. 1: 795. 1849. Type. Chile: Pöppig s.n.
Grimmia sessitana De Not., Atti Reale Univ. Genova 1: 704. 1869. Grimmia alpestris (Web. & Mohr) Schleich. var. sessitana (De Not.) I. Hagen, Kongel. Norske Vidensk. Selsk. Skr. (Trondheim) 1909(5): 22. 1909. Grimmia alpestris f. sessitana (De Not.) Loeske, Laubm. Eur. Part I: 105. 1913. Type. Italy: “In praeruptis infra Hospitium della Valdobbia, in valle Sessitana, legit. Carestia” (lectotype RO, designated by T. Cao & Vitt 1986). Synonymized by Muñoz 1998b.
Plants small, up to 1.0 cm high, dark green to blackish green, in dense tufts. Stems sparsely branched, with well developed central strand in cross section, lower part often covered with dense rhizoids. Leaves erect, imbricate when dry, spreading when moist, 1.8–2.0 mm long, narrowly lanceolate from an ovate base, keeled above, ending in smooth, hyaline hair-points, ca. 0.2–0.3 mm long, leaves in lower part of stem often muticous; margins narrowly recurved on one side from the middle to basal part of leaves; costa prominent, ending near the apex, with small median cells in cross section; upper cells rounded-quadrate, 8–10 µm wide, obscure, unistratose or in places bistratose at margins, with incrassate, straight or slightly sinuose walls; 2–4 rows of basal cells at margins hyaline, rectangular to short-rectangular, 15–23 µm × 9–13 µm, with distinctly thicker transverse walls than longitudinal walls; basal juxtacostal cells elongate, 30–33 µm × 8–10 µm, with thin, straight walls. Autoicous. Perichaetial leaves much larger than vegetative leaves, with long, smooth awns. Setae yellowish, ca. 2 mm long, straight, twisted to left when dry; capsules exserted, erect, ovoid to oblong-ovoid, yellowish brown, ca. 1 mm long, smooth or nearly so; exothecial cells short-rectangular, with thin, straight walls; stomata present near base of urns; annuli absent; opercula convex, with a blunt beak; peristome teeth erect, lanceolate, reddish brown, irregularly perforate and cleft above, outer and inner surface coarsely papillose above, papillose below. Calyptrae cucullate. Spores 9–11 µm in diameter, yellowish, granulose.