Resurrection of Leucobryum scalare Muell. Hal. ex M. Fleisch. (Bryophyta, Leucobryaceae) based on phylogenetic and morphometric evidence Author Tiwutanon, Patsakorn Department of Botany, Faculty of Science, Kasetsart University, 50 Ngamwongwan Road, Chatuchak, Bangkok, 10900, Thailand Author Chaiyasut, Kasidis Science Division, Mahidol University International College, Mahidol University, 999 Salaya, Phutthamonthon, Nakhon Pathom 73170, Thailand Author Lumbsch, H. Thorsten https://orcid.org/0000-0003-1512-835X Science & Education, The Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois, USA Author Kraichak, Ekaphan https://orcid.org/0000-0002-8437-2180 Department of Botany, Faculty of Science, Kasetsart University, 50 Ngamwongwan Road, Chatuchak, Bangkok, 10900, Thailand ekraichak@gmail.com text PhytoKeys 2023 2023-03-20 222 27 47 http://dx.doi.org/10.3897/phytokeys.222.98990 journal article http://dx.doi.org/10.3897/phytokeys.222.98990 1314-2003-222-27 1F52446F2D9752918DF7434226DD9C2B Leucobryum scalare Muell .Hal. ex M.Fleisch., Musci Buitenzorg 1: 143. 1904. Figs 8 , 9 Leucobryum aduncum var. scalare ( Muell .Hal. ex M.Fleisch.) A.Eddy, Handb. Males. Mosses 2: 11. 1990, syn. nov. Type . The Philippines . Luzon , Benguet : 5000 ft. alt., W. Micholitz 173 ( lectotype , designated by Yamaguchi 1993 , pg. 33: FH! [00290301]) . Leucobryum perichaetiale Dixon, J. Siam Soc., Nat. Hist. Suppl. 9(1): 11. 1932. Type : Thailand . Northern , Doi Suthep , ca. 1500 m alt., 6 Sept. 1914 . Kerr s.n. ( in herb. Dixon , ref. no. 8 ) ( holotype : BM [BM000866895]) . Leucobryum microleucophanoides Dixon ex A. Johnson , Gard. Bull. Singapore 20: 333. f. 9: m, 12. 1964. Type: Peninsular Malaysia . Kedah , Inchang Estate, on the decaying trunk, 24 Apr. 1940 . Spare s.n. ( in herb. Dixon , ref. no. 2941 ) ( holotype : BM [BM000866907]) . Description. Gametophytes usually form a small compact cushion, 0.5-3.3 cm long with leaves, yellowish green to whitish green, and brown to dark brown when dry. Stems erect, with many short branches, usually very dense; central strand absent in cross-section of stems. Leaves spiral and closely imbricate, forming a conical point at shoot apex when dry, 1.4-3.4 mm long, 0.4-0.9 mm wide, lanceolate to narrowly lanceolate, gradually or abruptly narrowed to subtubulous point from oblong to ovate base, cuneate, margin entire, acute at the apex, undulate and spinosely prorate on abaxial surface, sometimes undulate and papillosely prorate; laminae consisting 1-3 rows, lamina cells quadrate to rectangular, thin-walled; borders consisting 1-3 rows, border cells linear to narrowly fusiform, thin-walled; in cross-section of leaf base hyalocytes in 1-2 rows on the adaxial side and 2-3 rows on abaxial side, if 3 rows, usually 2 large rows and 1 small row; adaxial and abaxial side of median leaves consisting 1 row. Dioicous. Perichaetia terminal on short or long lateral branches; perichaetial leaves around sporophytes longer than ordinary leaves, ovate to lanceolate, abruptly slender to the point, cucullate, acuminate at apex. Sporophytes dicranoid. Setae elongate, erect, 1.5-1.7 cm long. Capsules subglobose to ovoid, inclined, 1.0-1.5 mm long, 0.4-0.5 mm diameter; opercula long rostrate; peristomes dicranoid. Calyptra cucullate. Figure 8. Gametophyte variation of different populations of Leucobryum scalare Muell .Hal. ex M.Fleisch. Figure 9. Leaf shape and size variation of different populations of Leucobryum scalare Muell .Hal. ex M. leisch Habitat. Usually found in more open sites, on logs, tree trunks, tree bases, branches, and rocks. Distribution. Mainland China, India, Sri Lanka, Myanmar, Thailand, Laos, Cambodia, Vietnam, Peninsular Malaysia, Philippines, Borneo, Sumatra, Java, Seram, New Guinea, and New Caledonia (Yamaguchi 1992; He 1995 ). Illustrations. Eddy 1990 (fig. 170A-E); Yamaguchi 1993 (Pls. XIX, 1-28; XX, 1-11; XXI, 1-15; XXII, 1-26). Key to the species

1	Gametophytes small to medium-sized, usually forming tufts, less branched, usually several branching in small gametophytes. Leaves falcate-secund, sometimes slightly erect, not forming a conical point at the shoot apex when dry	Leucobryum aduncum
-	Gametophytes small sized, usually forming a compact cushion, with many short branches, usually very dense. Leaves erect, sometimes falcate-secund when close to the substrate, arranged in spiral and closely imbricate, forming a conical point at shoot apex when dry	Leucobryum scalare