The genus Colura section Gamolepis (Lejeuneaceae, Marchantiophyta) in Malesian region, with the description of Colura sigmoidea Author Sangrattanaprasert, Jiroat Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand Author Chantanaorrapint, Sahut Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand Author Zhu, Rui-Liang text Phytotaxa 2019 2019-01-04 387 1 40 54 http://dx.doi.org/10.11646/phytotaxa.387.1.3 journal article 10.11646/phytotaxa.387.1.3 1179-3163 13725577 Colura meijeri Jovet-Ast, Rev. Bryol. Lichénol. 22: 290. 1953 . ( Fig. 2 ) Type: — INDONESIA . West Java : Pangerango Mountain, W . Meijer 291 ( holotype : BO !). Plants dull green, 0.6–1 cm long; shoots 1.2–2.3 mm wide; irregularly pinnately branched, branches of Lejeunea - type . Stems 125–138 μm in diameter, in transverse section consisting of 7 cortical cells (30–50 × 15–25 μm) and 3 medullary cells (30–38 × 20–33 μm); ventral merophytes of stem 2 cells wide. Rhizoids numerous, fasciculate at base of underleaves. Leaves slightly imbricate, spreading from stem at 30°–60° angle. Lobes 0.45–0.85 mm long, 0.36–0.4 mm wide; dorsal margin nearly flat, entire. Lobe cells thin-walled, trigones large, intermediate thickenings very distinct; marginal cells slightly rectangular or subquadrate, 30–45 × 20–30 μm; median cells hexagonal to slightly rectangular, 27–63 × 25–33 μm; basal cells slightly rectangular to hexagonal, 37–50 × 25–40 μm. Cuticle smooth. Oil bodies numerous per cell, homogenous, ellipsoid, 3–5 × 2–3 μm. Lobules narrowly tubular, flaring toward sac, 1.37– 1.42 mm long. Lobule sacs elliptic, strongly inflated, 0.8–0.97 mm long, 0.4–0.46 mm wide, sac surface mamillose, apex obtuse, without apical crest. Valves intermediate-type, elliptic, 137–150 × 105–113 μm, composed of one circle of 21–25 hyaline marginal and 25–34 median cells with one basal median cell, basal median cell adnate with a hinge cell not forming a sigmoid curve in outline. Hyaline papillae spherical to bulbous, 15–20 μm in diameter. Valve frame s outline semicircular with triseriate cells, ca. 160 μm wide. Underleaves distant, deeply bilobed, sinus obtuse; lobes lanceolate, 225–250 × 75–100 μm, 8–11 cells long, 4–5 cells wide at base; margin entire. Asexual reproduction by discoid gemmae, occurring on lobule sac apex and dorsal lobe of female bract; gemma cells subquadrate to isodiametric, consisting of 28–34 cells. Dioicous . Androecia terminal or intermediate on main stems and lateral branches; male bracts in 4–13 pairs, hemispherical, apical keel crenulate with one projecting cell row, free margin entire, hypostatic; bract lobes semicircular to oblong, 250–312 × 125–200 μm; bract lobules oblong to semicircular, 200–300 × 100–150 μm, bract lobules as large as bract lobes, antheridia 2 per bracts; male bracteoles bilobed, 60–124 × 90–140 μm. Gynoecia terminal on lateral branches with 1 pycnolejeunoid innovation; female bracts elliptic to slightly oblong, 700–1020 × 300–370 μm, apical keels entire; bract lobules narrowly oblong, 700–900 × 40–100 μm; female bracteoles oblong, ca. 100 × 90 μm, apex obtuse. Perianths elliptic to oblong, 1–1.3 mm long, 0.6–0.75 mm wide, with 3 keels; keels short, ridge-like, entire; beak 1 cell long. Sporophytes . Setae articulate, ca. 9 cells long; in transverse section with 4 inner and 12 outer cells. Capsules slightly spherical, ca. 330 μm in diameter, splitting to ± 2/3 of its length into four erect valves after dehiscence; capsule valves 330–350 × 220–230 μm, wall 2–3 stratose, hyaline. Outer layer of capsule valve apex formed by 1 quadrate cell; cells of upper half of valve rhombic to slightly rectangular, large, thin-walled; hinge rectangular, hinge cells rectangular to subquadrate, smaller than cells of upper half, thin-walled; marginal cells rectangular, formed by 1 row. Inner layer of capsule valve cells in centre rectangular, walls with nodular thickenings; marginal cells of upper half quadrate, walls nodulose, formed by 2 rows, marginal cells of lower half rectangular, wall smooth; basal cell subquadrate with smooth walls. Elaters of 2 types : marginal and additional; marginal elaters 22 per capsule, each valve contains 4 or 5 upper marginal elaters and 2 or no lower marginal elaters; upper marginal elaters attached to upper half of valve margin by one end, 237–300 μm long, 12–20 μm wide, hyaline, with irregular thickening, end attached to valve margin rounded, not expanded, free end dilated; lower marginal elaters attached to valve at both ends (near and parallel to basal margin), 190–210 μm long, 10–18 μm wide, hyaline, with irregular to annular thickening, upper end narrowly tapered, lower end obtuse; additional elaters 4 per capsule (1 per each valve), ca. 280 μm long, 10 μm wide, hyaline, with smooth to irregular thickenings, attached along their whole length to median part of valve, even upon dehiscence. Spores green, irregular-oblong or elongate-rectangular, 62–68 × 32–38 μm; spore surface covered with irregular lamellae; sporelings Lejeunea - type . Habitat and ecology: — Colura meijeri was found growing densely on living leaves in montane forest at 1100– 1260 m elevation (up to 1400 m at Pangerango Mountain, Indonesia ( Jovet-Ast 1953 )). This species may grow associated with other Colura species such as C . acroloba (Montagne ex Stephani (1890: 97)) Jovet-Ast (1953: 297) and C . karstenii Jovet-Ast (1953: 229) . Distribution: — Indonesia , Japan ( Jovet-Ast 1953 ), new to Thailand . Selected specimens examined: — JAPAN . Kumamoto Prefecture : Hitoyoshi , 17 August 1947 , Mayebara 703 ( PC ) ; THAILAND . Nakhon Nayok : Mueang Nakhon Nayok , Khao Yai National Park , Pha Dieo Dai , 14°21ʹ59.39ʺN , 101°23ʹ20.19ʺE , 1190–1260 m , 14 November 2013 , Sangrattanaprasert 26/13 ( PSU ), Pha Trom Chai, 14°21ʹ30.22. N , 101°22ʹ51.60ʺE , 1115–1220 m , 1 June 2015 , Sangrattanaprasert 333/15 , 337/15 ( PSU ) . Taxonomic notes: — Colura meijeri resembles C . valida Jovet-Ast (1961: 6) in having rather large lobule sac with entire and obtuse apex, flattened dorsal leaf margin, and large underleaf lobes. Nevertheless, C. meijeri differs from C . valida , by the larger valve consisting of 21–25 hyaline marginal cells and 25–34 median cells, and elliptic to oblong perianth with 3 ridge-like keels.