The lichen family Physciaceae in Thailand-I. The genus Pyxine Author Mongkolsuk, Pachara Lichen Research Unit, Biology Department, Faculty of Science, Ramkhamhaeng University, Ramkhamhaeng road 24, Bangkok, 10240 Thailand. Email: pm-tamrapap @ ru. ac. th Author Meesim, Sanya Lichen Research Unit, Biology Department, Faculty of Science, Ramkhamhaeng University, Ramkhamhaeng road 24, Bangkok, 10240 Thailand. Email: pm-tamrapap @ ru. ac. th Author Poengsungnoen, Vasun Lichen Research Unit, Biology Department, Faculty of Science, Ramkhamhaeng University, Ramkhamhaeng road 24, Bangkok, 10240 Thailand. Email: pm-tamrapap @ ru. ac. th Author Kalb, Klaus Lichenologisches Institut Neumarkt, Im Tal 12, D- 92318 Neumarkt, Germany. Email: klaus. kalb @ arcor. de & University of Regensburg, Institute for Botany, Universitätsstra e 31, D- 39040 Regensburg, Germany text Phytotaxa 2012 2012-07-13 59 1 32 54 http://biotaxa.org/Phytotaxa/article/view/phytotaxa.59.1.2 journal article 10.11646/phytotaxa.59.1.2 1179-3163 5061495 14. Pyxine profallax Kalb , Bibl. Lichenol. 99: 243 (2009). Holotype : PAPUA NEW GUINEA . Central District ; around Woitape , ca. 1600 m , 19 October 1975 , Kurokawa 9309 ( TNS !). Thallus corticolous, 3–5 cm wide, adnate. Lobes radiating, discrete to ± imbricate, plane to slightly concave, 0.8–1.0 mm wide, subrotund to truncate at the apices. Upper surface whitish to grey or brownish grey, sparsely pruinose at the lobe tips or epruinose; polysidiangia, isidia and soralia absent. Pseudocyphellae distinct, marginal and laminal, irregular, becoming reticulate on the upper surface. Medulla uniformly white. Lower surface black in the centre, paler towards the margin; rhizines ± dense, furcate. Apothecia common, obscurascens - type , 0.5–1.0 mm wide; disc black, not pruinose. Internal stipe distinct, white, K-, P-. Ascospores 16–22 × 6–8 μm. Pycnidia laminal, immersed to slightly sessile, black; conidia bacilliform, 3–4 × 1 µm . Chemistry: Cortex K+ yellow, C-, KC-, P+ yellow, UV-; medulla K+ yellow → red, C-, P+ orange; containing atranorin (minor), chloroatranorin (minor), norstictic acid (major), testacein (submajor), unknown terpenes showing the same array as P. fallax (minor). Distribution and habitat :—A very rare species, corticolous in a lower montane scrub. Also in Papua New Guinea ( holotype ). Notes :— Pyxine profallax is characterized by the adnate thallus, the absence of soredia, isidia and polysidiangia, the uniformly white medulla with norstictic acid, cortical atranorin, and obscurascens - type apothecia. P. philippina and P. schmidtii are very similar as both lack vegetative propagules and contain additional testacein, but the latter lacks norstictic acid and the former contains a different array of terpenes. Material from Thailand examined :— Loei ; Phu Luang Wildlife Sanctuary , Lan Suriyan , on bark in a lower montane scrub, 1473 m , 17°16'44'' N , 31°07'02'' E , 25 June 2008 , S. Meesim 29 ( RAMK 17620 ) .