Colura tenuicornis (A. Evans) Steph.

Singh, Sushil Kumar, Pócs, Tamás, Singh, Devendra & Kumar, Shashi, 2020, A synopsis of Colura (Dumort.) Dumort. (Marchantiophyta: Lejeuneaceae) in India, Cryptogamie, Bryologie 20 (10), pp. 111-129 : 126

Colura tenuicornis (A. Evans) Steph. ( Figs 7 A-P; 8H, I)

Species Hepaticarum 5: 942 (1916).

SPECIMENS EXAMINED. — India. Arunachal Pradesh, Dibang Valley district, on way to Dessali from Hunli, c. 1150 m, 15.01.1984, D. K. Singh 675C/1984 (ASSAM);Lower Dibang Valley district, Chekhopani, c. 2000 m, 17.XI.2000, D.K. Singh 98169B (BSD); Meghalaya, East Khasi Hills, Elephant falls, 25°32’12.8”N, 91°49’21.03”E, 1769 m, 02.V.2016, Shasi Kumar TSLI - 2105 & 23.VII.2016, TSLI - 2193, 2194 (ASSAM); near Mawkajem, 25°25’23”N, 91°51’47”E, 1715 m, 25.XI.2017, S. K. Singh & Party TSLI - 3796 (ASSAM); Sikkim, North district, Thulung, 27°38’13.3”N, 88°26’29”E, c. 2449 m, 03.IV.2013, D. Singh 60598B (CAL); East district, Pangthang, c. 1988 m, 18.IX.2007, D. Singh 40967 (CAL); ½ km before Bojogari falls on way from Burtak to Pangthang, c. 1850 m, 28.VII.2008, B. S. Kholia 41103C (CAL); West district, between Hilley and Barsey, c. 2784 m, 26.V.2008, K. Das 41091B (CAL); Hilley, c. 2766 m, 28.V.2008, K. Das 41096C (CAL), 08.III.2010, D. Singh & S. Majumdar 47562A (CAL); 12th mile from Hilley towards Okhrey, c. 2700 m, 12.III.2010, D. Singh & S. Majumdar 47740B, 47746C (CAL); South district, Maenam Wildlife Sanctuary, 27°18’42.5”N, 088°21’54.5”E, c. 2192 m, 01.VI.2011, D. Singh 51720A, 51745B; West Bengal, Darjeeling district, Takdah, c. 1650 m, 17.I.2005, D. Singh & M. Dey 36218 (CAL).

HABITAT. — Foliicolous, growing in association with Cololejeunea latilobula , C. longifolia , C. pseudofloccosa , C. truncatifolia , Drepanolejeunea erecta , D. fleischeri , D. longii , Lejeunea anisophylla , L. discreta , L. flava , L. wallichiana , Leptolejeunea balansae , L. elliptica , Microlejeunea punctiformis , in moist and shady places at elevation of 1200-2800 m a.s.l.

DISTRIBUTION. — India [Arunachal Pradesh, Meghalaya-present study, Sikkim, West Bengal ( Singh et al. 2016)], Bhutan, Cambodia, China, Comoro Archipelago, Fiji, Galapagos, Hawaii, Indonesia, Japan, Malaysia, Nepal, Papua New Guinea, Sri Lanka, Taiwan, Vietnam, Africa, South America ( Tixier 1979; Yano 1984; Grolle & Piippo 1984; Piippo 1990; Pócs 1993; Zhu & Long 2003; Staples & Imada 2006; Yamada & Iwatsuki 2006; Pradhan & Joshi 2009; Wigginton 2009; Söderström et al. 2010; Söderström et al. 2011; Gradstein & Ziemmeck 2011; Chuah-Petiot 2011; Wang et al. 2011; Long & Rubasinghe 2014; Bakalin & Van Sinh 2016).

DESCRIPTION

Plants

Green when fresh, pale yellowish green in herbarium; shoots 2-6 mm long, (1.0-) 1.8-2.4 mm wide including leaves; branching irregular.

Stem

In cross section suborbicular in outline, 52.5-82.5 × 52.5- 75.0 µm, 4 cells across diameter; cortical cells 7, subquadrate-rectangular or polygonal, 17.5-32.5 × 10.0-22.5 µm, thin-walled; medullary cells 3, polygonal, 15.0-25.0 × 10.0- 17.5 µm, cells thin-walled. Ventral merophytes 1-2 cells wide.

Leaves

Contiguous-remote, obliquely-widely spreading, leaf lobes lanceolate, 0.25-0.45 mm long, 0.12-0.20 mm wide, margin entire, dorsal margin slightly arched, ventral margin nearly straight-slightly arched; marginal leaf cells towards apex rectangular-polygonal or subquadrate, 12.5-20.0 × 7.5-12.5 µm; median leaf cells pentagonal-hexagonal, 15.0-

27.5 × 10.0-17.5 µm; basal leaf cells elongated pentagonal - hexagonal or rectangular, 25.0-45.0 × 10.0-17.5 µm; cells thin-walled without trigones and intermediate thickenings; cuticle smooth; oil-bodies 6-14 per leaf cell, spherical, 2.0- 3.5 µm in diameter, or elliptical, 5.0-7.2 × 2.5-4.0 µm; leaf lobules inflated, 2-3 times as long as the lobe, widest at middle, 0.75-1.25 mm long, 0.13-0.17 mm wide, sac cylindrical-lanceolate forming a long tubular beak towards apex, beak c. ½ as long as leaf lobule, margin entire; valve elliptical-ovoid, 87.5-92.5 × 65.0-72.5 µm, composed of 11-14 median cells surrounded by a ring of 15-16 hyaline cells, hinge distinct.

Underleaves

Remote, (2.5-) 3-4 times as wide as the stem, 0.16-0.19 mm long, 0.13-0.25 mm wide, deeply bilobed, sinus wide, lobes divergent, linear-lanceolate, 6-8 cells long, 2-3 cells wide at base, apex subacute, margin entire. According to Jovet-Ast (1953) monoicous. Androecial branches on Indian plants not seen.

Androecia and gynoecia

Androecial branches on Indian plants not seen; gynoecia on short or long branches, with one subfloral innovation; bract lobe narrowly oblong, (0.25-) 0.37-0.51 mm long, 0.10- 0.16 mm wide; bract lobule, (0.2-) 0.31-0.45 mm long, (0.04-) 0.07-0.10 mm wide; bracteoles not seen. Perianth obovate, 0.62-0.81 mm long, 0.22-0.27 mm wide, mouth with five large horn-like keels (two lateral, two ventral and one dorsal); keels ⅓ as long as the perianth, subcylindrical, apices sharply acute, margin entire, surface smooth. According to Jovet-Ast (1953) monoicous.

Mature sporophytes

Not seen.