Pyxine sorediata (Ach.) Mont.

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

18. Pyxine sorediata (Ach.) Mont. , in Ramón de la Sagra, Hist. phys., polit. nat. Cuba, Bot. Plant. Cellul. 2: 188 (1842).

Type:— Lecidea sorediata Ach., Syn. meth. lich.: 54 (1814). Lectotype (selected by Kalb 1987: 74 [as holotype]):—in America septentrionale, Müh/eⁿberg; (H-ACH 378!, isolectotypes: S!, UPS!).— Physcia glaucovirescens Nyl., Syn. meth. lich. 1(2): 419 (1860) = Pyxine glaucovirescens (Nyl.) Aptroot, Crypt., Bryol. Lichenol. 9: 146 (1988). Lectotype (selected by Aptroot 1988b: 146):— AUSTRALIA. Queensland; Morton [Moreton] Bay, Verreaux 1846; ( PC n.v., fide A. Aptroot, loc. cit.; isolectotype:—( H). For further synonymy see Kalb (1987).

Thallus corticolous as well as saxicolous, 3–8 (–20) cm wide, adnate to loosely adnate. Lobes radiating, contiguous to imbricate, plane to slightly concave, 0.6–1.3 mm wide, subrotund at the apices. Upper surface yellowish grey to brownish grey, lead-grey or blue-grey, distinctly pruinose; pruina punctiform towards lobe apices; polysidiangia and isidia absent. Pseudocyphellae very distinct at the margins, often grey-pruinose and becoming reticulate. Soralia initially marginal, developing from fissures, then laminal and orbicular, occasionally becoming corticate and developing into pseudoisidia; soredia granular, dirty white or grey. Medulla lemon-yellow above; lower part yellow-brown or yellow-orange. Lower surface black in the centre, paler towards the margin; rhizines ± dense, black to blue-black, furcate. Apothecia rare, obscurascens - type, 0.5–1.4 mm wide; disc epruinose. Internal stipe distinct; upper part dark orange, K + red, P-, C-, KC-; lower part whitish, K-, P-, C-, KC-. Ascospores 14–19 × 6–8 µm. Pycnidia rare, laminal immersed in small warts in thallus; conidiospores bacilliform, 3–4 × 1 µm.

Chemistry: Cortex K + yellow or K-, C-, KC-, P + pale yellow or P-, UV –; medulla K-, C-, P-; containing atranorin (minor, or usually trace), chloroatranorin (trace), unknown terpenes (major), unknown pigment (minor).

Distribution and habitat:—A rare species on rocks and bark in coniferous and dry dipterocarp forests. Also in Europe, North, Central and South America, Africa, Australia, Asia and the Pacific islands.

Notes:—This species is characterized by the coarse, dirty white to grey, granular soredia, the absence of isidia and polysidiangia, the yellow to yellow-orange medulla, the prominent marginal pseudocyphellae and the presence of cortical atranorin. Pyxine endochrysina Nyl. is superficially similar, but it is esorediate and has nodular to squamulose or lobulate, marginal isidia.

Material from Thailand examined:— Chiang Mai; Queen Sirikit Botanic Garden, on the trunk of Syzygium claviflora in dry dipterocarp forest, 750 m, 18°53'54'' N, 98°51'38'' E, 1 July 1994, K . Boonpragob et al. 2667 ( RAMK).— Loei; Phu Luang Wildlife Sanctuary, Lon Tae Forest Ranger Station, Pha Kop , on the bark of an unidentified tree in coniferous forest, 1343 m, 17°11'13'' N, 101°33'58'' E, 12 November 2009, S . Meesim & K . Buaruang 599 ( RAMK) .