Pyxine meissnerina Nyl., Bull. Soc. Linn. Normandie

Mongkolsuk, Pachara, Meesim, Sanya, Poengsungnoen, Vasun & Kalb, Klaus, 2012, The lichen family Physciaceae in Thailand-I. The genus Pyxine, Phytotaxa 59 (1), pp. 32-54 : 46-47

11. Pyxine meissnerina Nyl., Bull. Soc. Linn. Normandie , 2, 7 (1874) ['1873']: 164.

Type :— INDIA. West-Bengalia, 1867, Kurz 164. Lectotype (designated by Swinscow & Krog 1975a: 59): (H-NYL. 31775!).

Thallus corticolous or saxicolous, 2–7 cm wide, adnate to tightly adnate. Lobes radiating, discrete to ± contiguous, plane to slightly concave, in older thalli becoming slightly convex in the centre, 0.5–1.3 mm wide, subrotund to truncate at the apices. Upper surface pale grey, grey or grey-brown, pruinose in extensive patches near the apices, the pruina ± glistening; marginal soredia present. Pseudocyphellae not prominent, restricted to the margins, developing into soralia, sometimes very slow so that the thallus remains without vegetative propagules for a long time. Medulla uniformly creamy to sulfur yellow. Lower surface black in the centre, paler towards the margin; rhizines ± dense, furcate. Apothecia not common, obscurascens - type, 0.5–1.3 mm wide; disc epruinose, but margin sometimes white pruinose. Internal stipe distinct; upper part brown, K + wine red, P-; lower part white, K-, P-. Ascospores 16–22 × 6–7 µm. Pycnidia ± common, immersed in small warts on thallus with an exposed black ostiole. Conidia 3–5 × 1–1.2 µm.

Chemistry: Cortex K + yellow, UV-; medulla K + slightly violet in patches, C-, KC+ violet, P + orange; containing atranorin (major), terpenes (major or minor), unknown pigment (minor or trace).

Distribution and habitat:—Very common on bark and rock in dry dipterocarp and mixed deciduous forests. Also in India, Nepal and Africa.

Notes:— Pyxine meissnerina is characterized by the cortical atranorin, the patchy pruina on the lobe tips, the marginal pseudocyphellae developing into soralia, the creamy to sulfur yellow medulla and apothecia of the obscuracens - type with a brown, K+ wine red internal stipe. Pyxine subcinerea is very similar, but it has a UV+ orange thallus containing lichexanthone and the two species contain very different arrays of terpenes. Pyxine endolutea Kalb is also similar. That species contains atranorin and has a sulfur yellow medulla, but it lacks soralia. In some cases the production of soralia starts very late so that many younger specimens lack vegetative propagules. Consequently in the key, we have included this species as being both sorediate and nonsorediate.

Selected material from Thailand examined:— Chiang Mai; Queen Sirikit Botanic Garden, on the bark of Stereospermum neuranthum in dry dipterocarp forest, 730 m, 18°49' N, 98°59' E, 9 November 1994, K . Boonpragob et al. 3548, 3567, 3568 ( RAMK).— Chiang Mai; Mae Rim, along a big pond called ' Huay Tueng tao Reservoir' , ca. 6 km NNW of Chiang Mai, on bark in a dry dipterocarp forest, 360 m, 18°52'11'' N, 98°56'28'' E, 16 March 2008, K . Kalb (hb. Kalb 37048).— Loei; Phu Luang Wildlife Sanctuary, Phu Luang Wildlife Research Station , on rock in a lower montane rainforest, 923 m, 17°20'35'' N, 101°31'26'' E, 26 March 2009, S . Meesim 199 ( RAMK 17631 ).— Loei; Phu Luang Wildlife Sanctuary, Nam Chan Forest Ranger Station , on rocks in dry evergreen forest, 397 m, 17°20'49'' N, 101°33'26'' E, 28 July 2009, S . Meesim & K . Buaruang MSPL 315 , 316 ( RAMK).— Loei; Phu Luang Wildlife Sanctuary, Phu Ho Forest Ranger Station , on the trunk of Bombax ceiba in mixed deciduous forest, 569 m, 17°07'09'' N, 101°38'39'' E, 29 July 2009, S . Meesim & K . Buaruang MSPL 280 ( RAMK).— Loei; Phu Luang Wildlife Sanctuary, Phu Ho Forest Ranger Station , on the bark of an unidentified tree in mixed deciduous forest, 569 m, 17°07'06'' N, 101°38'39'' E, 29 July 2009, S . Meesim & K . Buaruang MSPL 425 ( RAMK).— Loei; Phu Luang Wildlife Sanctuary, Phu Ho Forest Ranger Station , on the bark of Terminalia glaucifolia in mixed deciduous forest, 569 m, 17°07'09'' N, 101°38'39'' E, 29 July 2009, S . Meesim & K . Buaruang MSPL 432 , 433 , 434 ( RAMK).— Loei; Phu Luang Wildlife Sanctuary, Phu Ho Forest Ranger Station , on the bark of an unidentified tree in dry dipterocarp forest, 569 m, 17°06'43'' N, 101°37'51'' E, 30 July 2009, S . Meesim & K . Buaruang MSPL 449 , 457 ( RAMK).— Nakhon Ratchasima; Khao Yai National Park, Khao Lookchang , on the bark of Delonix regia in dry dipterocarp forest, 1100 m, 14°32' N, 101°40' E, 20 August 1997, K . Boonpragob et al. 8243 ( RAMK).— Saraburi; Khao Yai National Park, Muak Lek , on the bark of an unidentified tree in mixed deciduous forest, 300 m, 14°34' N, 101°12' E, 17 January 2000, P . Mongkolsuk 16405.2 ( RAMK) .