Pyxine philippina Vain. , The Philipp. Journ. Sci., C

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 : 48

13. Pyxine philippina Vain., The Philipp. Journ. Sci., C , 8 (2): 110 (1913).

Lectotype (selected by Kashiwadani 1977: 163):— PHILIPPINES. Luzon ; Benguet, ad corticem arborum frondosarum, May 1911, E. D. Merrill 7934 ( TUR-VAIN 8707 !).— Pyxine glaucescens Vain. The Philipp. Journ. Sci., C , 8: 109 (1913) . Holotype: PHILIPPINES. Comiran Island, Sulu Sea , ad corticem arboris frondosae, September 1910, E. D. Merrill s.n. ( TUR-VAIN 8705 !) .

Thallus corticolous, 2–5 cm wide, adnate to loosely adnate. Lobes radiating or irregular, contiguous to imbricate, plane to partly convex, 0.5–1.4 mm wide, subrotund at the apices. Upper surface whitish to pale greenish grey or yellow-grey, faintly pruinose towards the lobe tips or epruinose; polysidiangia, isidia and soralia absent. Pseudocyphellae marginal and laminal, irregular, linear or becoming reticulate. Medulla uniformly white. Lower surface black in the centre, paler towards the margin; rhizines ± dense, furcate. Apothecia common, obscurascens - type, 1–3 mm wide; disc black, not pruinose. Internal stipe distinct, white to pale brown, K-, P-. Ascospores 15–23 × 6–8 µm. Pycnidia not seen.

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 (minor), unknown terpenes showing the same array as P. retirugella Nyl. (minor).

Distribution and habitat:—Very rare on bark in a mixed deciduous forest. Also in Australia, Asia, Africa, South America and the Pacific (Hawaiian Islands and Micronesia).

Notes:— Pyxine philippina is characterized by the adnate thallus, the absence of soredia, isidia and polysidiangia, the uniformly white medulla, cortical atranorin and obscurascens - type apothecia with an internal stipe that is brownish in the upper part. P. schmidtii Vain. , which also produces testacein, is morphologically very similar in lacking any vegetative propagules, but can easily be distinguished by the absence of norstictic acid in the medulla. P. profallax is morphologically also very similar, but this species differs by a different suite of terpenes.

Material from Thailand examined:— Pitsanulok ; Phu Hin Rongkla National Park, air raid shelter point, on the bark of unidentified tree in mixed deciduous forest, 560 m, 18 September 2006, S. Meesim 21506 ( RAMK) .