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 6. Pyxine cognata Stirt. , Proc. Royal Phil. Soc. Glasgow 11: 311 (1879). Holotype :— INDIA . Nilgherries [Nilgiri]; A . Watt s. n. ( BM !).— Pyxine berteriana var. himalaica D. D. Awasthi , Phytomorphology 30: 366 (1982) . Holotype :— INDIA . Almora district ; Uttar Pradesh , on way to Kasardevi , ca. 1930 m , on bark, 12 June 1956 , D. D. Awasthi 3476 ( LWG !) . Thallus corticolous, 2–6 cm wide, adnate to tightly adnate. Lobes radiating, discrete to ± contiguous, plane to slightly concave, in older thalli becoming slightly convex in the centre, 0.3–1.0 mm wide, subrotund to truncate at the apices. Upper surface white to whitish grey or grey-brown, pruinose in extended patches near the apices, the pruina ± glistening; polysidiangia, isidia and soralia absent. Pseudocyphellae not prominent, usually retricted to the margins, rarely laminal or becoming subreticulate, often obscured by spreading pruina. Medulla orange in upper part; lower medulla white. Lower surface black in the centre, paler towards the margin; rhizines ± dense, furcate. Apothecia common, obscurascens - type , 0.3–1.0 mm wide; disc epruinose. Internal stipe distinct, upper part orange-red, K + pale red, P-, C-, KC-, lower part much paler or white, K-, P-, C-, KC-. Ascospores (13–) 16–20 × 6–7 μm. Pycnidia not seen. Chemistry: Cortex K-, UV + yellow; medulla K-, C-, KC-, P-; containing lichexanthone (major), terpenes (major or minor), unknown pigment (minor or trace). Distribution and habitat :—Uncommon on bark in dry dipterocarp, dry evergreen and mixed deciduous forests. Also in Australia , China , India , Java and South America; not yet known from Africa. Notes :— Pyxine cognata is characterized by the cortical lichexanthone, the absence of vegetative propagules, the partly orange medulla and apothecia of the obscuracens - type with an orange-red, K+ pale red internal stipe. Pyxine berteriana is similar, but it has broader, sparsely pruinose lobes and a medulla that is partly yellow. The two species contain very different arrays of terpenes ( Kalb, 1987 , pl. 11). Material from Thailand examined :— Chiang Mai ; Queen Sirikit Botanic Garden , on Melia azedarach , hill evergreen forest, 1170 m , 30 June 1994 , K . Boonpragob 2278 ( RAMK ).— Chiang Mai ; Queen Sirikit Botanic Garden , on Stereospermum neuranthum , dry dipterocarp forest, 730 m , 18°53'54'' N , 98°51'38'' E , 30 June 1994 , K . Boonpragob 3582 ( RAMK ).— Loei ; Phu Luang Wildlife Sanctuary , Pak Dang Forest Ranger Station , on the bark of an unidentified tree in dry evergreen forest, 750 m , 17°10'42'' N , 101°21'48'' E , 22 May 2009 , S . Meesim 259 ( RAMK ).— Loei ; Phu Luang Wildlife Sanctuary , Phu Ho Forest Ranger Station , on the bark of Tamarindus indica in mixed deciduous forest, 569 m , 17°07'13'' N , 101°34'30'' E , 29 July 2009 , S . Meesim 338 ( RAMK ).— Loei ; Phu Luang Wildlife Sanctuary , Nam Chan Forest Ranger Station , on the bark of an unidentified tree in mixed deciduous forest, 397 m , 17°20'49'' N , 101°33'29'' E , 28 July 2009 , S . Meesim 344 ( RAMK ).— Loei ; Phu Luang Wildlife Sanctuary , Nam Chan Forest Ranger Station , on the bark of Saraca indica in mixed deciduous forest, 397 m , 17°20'49'' N , 101°33'29'' E , 28 July 2009 , S . Meesim 347, 348 ( RAMK ).— Nakhon Ratchasima ; Khao Yai National Park , on the bark of Roystonea regia in secondary forest, 385 m , 14°33' N , 101°40' E , 15 January 2000 , N . Homchantara 16269 ( RAMK ) .