On taxonomic status of Macromitrium leptocarpum and M. subleptocarpum, with comments on M. sulcatum (Bryophytea, Orthotrichaceae) Author Yu, Jing Author Li, Dandan Author Li, Yan Author Guo, Shuiliang text Phytotaxa 2018 2018-07-20 361 3 287 293 http://dx.doi.org/10.11646/phytotaxa.361.3.4 journal article 10.11646/phytotaxa.361.3.4 1179-3163 13705363 Macromitrium sulcatum (Hooker 1819: 156) Bridel (1826: 319) var. leptocarpum Brotherus (1899: 318) J. Ying, D. D. Li, Y Li & S. L. Guo, comb nov. ( Figs. 1–2 ) Basionym— Macromitrium leptocarpum Brotherus (1899: 318) . Protologue:—Coorg: on trees in exposed situations near mercara (n. I. 7, 69); Mercara, exposed granite rocks (n. 68); dry jungle near Verajpet (n. I 32). TYPE :— INDIA . Exposed granite rocks, Mercara , Coorg , Coll. T . La Walker 68 , Dec 1897 ( lectotype H-BR 264004!, designated here) ; INDIA , Dry jungle near Verajpet , Coorg , Coll , T . L . Walker I32 , Dec. 1897 . ( isosyntype , MICH525887 !, BM000982483 !) . = Macromitrium subleptocarpum Dixon & P. de la Varde (1930: 179) , syn. nov . Protologue :—Hab. Mahableshwar, Western Chats , Jan. 1928 ; coll. E . Blatter (376), type . Ibidem (379) . TYPE :— INDIA . Mahableshwar , Western Ghats , Jan. 1928 ; coll. E . Blatter 376, type, Herb. H . N . Dixon ( isotype , BM000982487 !) ; Mahableshwar , W . Ghats , 1928, E . Blatter 379, co-type, Herb. H . N . Dixon (isoparatype: BM000982488 !, US 00070280!). Plants medium to large, forming dense yellowish-green mats, dark-brown below. Stems creeping, with dense, short, stout, erect branches about 4–10 mm high, densely leaved, with dense reddish rhizoids. Stem leaves different from branch leaves, irregularly flexuose-twisted when dry, spreading when moist, entire, 1.0– 1.5 mm long, 0.3–0.4 mm wide, narrowly-triangular to ovate-lanceolate, acute at apex, costa single, ending in or a few cells below apex. Branch leaves crisped and twisted when dry, flexuose-spreading when moist, margins entire to irregularly denticulate in upper portion, oblong lingulate to oblong-lanceolate, 1.8–2.5 mm long, 0.3–0.4 mm wide, the apex obtuse, acute or broadly acuminate, keeled, slightly plicate below; margins plane or occasionally narrowly recurved on one side; costae single, ending a few cells below apex; upper cells subquadrate, quadrate or quadrate-rotund, 2.5–4.0 μ m wide, flat to slightly bulging, smooth, in regularly oblique rows; median cells slightly elongate, quadrate, short-rectangular, 4–5 μ m long, 3.0–4.0 μ m wide, in longitudinal rows, gradually becoming rectangular farther down; low cells rectangular, 9–15 μ m long, 3.0–4.0 μ m wide, thick-walled, incrassate and porose; basal cells along costa rectangular to irregularly rectangular, thin-walled, smooth and pellucid, 15–25 μ m long, 8–10 μ m wide, distinctly larger than their ambient cells, appearing as a “cancellina region”, others elongate, rectangular to sublinear, 14.0–30.0 μ m long, 2.5–4.0 μ m wide, thick-walled, incrassate and porose, often with a tuberculate papilla; outmost marginal cells at or near leaf insertion slightly differentiated, enlarged, hyaline. Autoicous. Perichaetia subterminal on branches. Inner perichaetial leaves differentiated, shorter than branch leaves, oblong-ligulate to broadly oblong, often plicate in basal part, 1.0– 1.5 mm long, 0.3–0.4 mm wide, broadly acute at apex, with percurrent to excurrent costa. Papaphyses numerous and long. Setae 5.0 – 17 mm long,smooth, twisted to left. Capsules cylindric, dark-purple, 2.5–3.0 mm long, 0.6–0.8 mm wide, smooth when dry. Peristome consisting of a low double membrane, exostome yellowish, densely papillose, endostome hyaline. Operculum erect, conic-rostrate. Spores anisosporous, vary much in size, 12–35 μ m, finely papillose. Calyptra naked, campanulate, ca. 3.0 mm long, weakly lacerate below. Macromitrium sulcatum var. leptocarpum is similar to M. sulcatum var. sulcatum , the former has smooth, long or obloid cylindric capsules ( Figs 1–2 ), and the latter has sulcate (strongly furrowed and ovate-obloid) capsules ( Fig. 3 ).