Pyxine subcinerea Stirt. , Trans. Proc.

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 : 51-52

19. Pyxine subcinerea Stirt., Trans. Proc. New Zealand Inst. 30: 397 (1898).

Holotype:— AUSTRALIA. Queensland; [locality unknown], F. M. Bailey 22; ( BM!). For further synonymy see Kalb (1987).

Thallus 3–8 cm wide, adnate to loosely adnate, subdichotomously lobate. Lobes radiating, contiguous to imbricate, plane but often slightly concave towards the tips, 0.3–0.7 (–1.0) mm wide, subrotund to subtruncate at the apices. Upper surface yellowish grey to grey to brownish grey or olive-grey, pruinose; pruina densely punctiform towards the lobe tips or forming larger plates within the thallus, often glistening; polysidiangia and isidia absent. Pseudocyphellae distinct at the margins, often spreading laminally, rarely reticulate. Soralia marginal or submarginal and linear, then laminal and punctiform, often coalescing; soredia farinose. Medulla lemon yellow to yellow above, very thin below, white. Lower surface black in the centre, paler towards the margin; rhizines ± dense, furcate. Apothecia common, obscurascens - type, 0.3–1.5 mm wide; disc epruinose. Internal stipe indistinct; upper part red-brown, K + purple, P-; lower part white, K-, P-. Ascospores 13–20 × 6–8 µm. Pycnidia rare, laminal immersed in small warts in thallus; conidiospores bacilliform, 3–4 × 1 µm.

Chemistry: Cortex K-, UV + yellow; medulla upper part K-, C-, KC-, P + orange, lower part K-, C-, KC-, P-; containing lichexanthone (major), terpenes (major or minor), unknown pigment (minor or trace).

Distribution and habitat:—Occurs on rock, wood and bark in dry dipterocarp, lower montane and mixed deciduous forests. This mainly pantropical species often extends into subtropical and temperate regions.

Notes:— Pyxine subcinerea is characterized by the marginal soralia with farinose soredia, the yellow medulla, obscurascens - type apothecia and the presence of lichexanthone in the upper cortex. Pyxine meissnerina is very similar in its overall habitus, but this species is readily separated by a P- upper part of the medulla and a UV- cortex which contains atranorin.

Material from Thailand examined:— Chiang Mai; Queen Sirikit Botanic Garden, on Quercus mespilifolioides in an open, dry dipterocarp forest, 570 m, 18°53'54'' N, 98°51'38'' E, 1 July 1994, P . Mongkolsuk 1473 ( RAMK 17619 , 17633 , 17634 ).— Loei; Phu Luang Wildlife Sanctuary, Nam Chan Forest Ranger Station , on the trunk of Saraca indica in mixed deciduous forest, 397 m, 17°20'49'' N, 101°33'29'' E, 28 July 2009, S . Meesim 355 ( RAMK).— Loei; Phu Luang Wildlife Sanctuary, Phu Luang Wildlife Research Station , on the bark of an unidentified tree in lower montane rainforest, 923 m, 17°20'34'' N, 101°30'26'' E, 12 November 2008, S . Meesim & K . Buaruang 186 ( RAMK).— Loei; Phu Luang Wildlife Sanctuary, Phu Ho Forest Ranger Station , on the bark of an unidentified tree in lower montane rainforest, 923 m, 17°20'34'' N, 101°30'26'' E, 12 November 2009, S . Meesim & K . Buaruang MS 0186 ( RAMK).— Loei; Phu Luang Wildlife Sanctuary, Nam Chan Forest Ranger Station , on the trunk of Saraca indica in mixed deciduous forest, 397 m, 17°20'49'' N, 101°33'29'' E, 28 July 2009, S . Meesim & K . Buaruang MSPL 355 ( RAMK) .