Pyxine farinosa Kashiw., Bull. Natl Sci. Mus.

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

Pyxine farinosa Kashiw., Bull. Natl Sci. Mus. , Tokyo, B, 3 (2): 67 (1977).

Holotype:— MICRONESIA. Caroline Islands; Yap Island , 6 August 1939, F. Fujikawa 52 ( TNS!). For further synonymy see Elix (2009).

Thallus 2–5 cm wide, adnate. Lobes radiating, discrete to imbricate, plane to slightly convex, 0.3–1.2 mm wide, subtruncate at the apices. Upper surface white to yellowish white or yellowish grey, sparsely pruinose at the lobe tips or epruinose; polysidiangia and isidia absent. Pseudocyphellae ± distinct, marginal and laminal, irregular or becoming reticulate. Soralia laminal or occasionally apical, distinctly elevated, orbicular, subglobose; soredia farinose, white to yellow-white. Medulla upper part orange to orange-red, lower part white. Lower surface black in the centre, paler towards the margin; rhizines ± dense, furcate. Apothecia rare, obscurascens - type, 0.5–2.0 mm wide; disc epruinose. Internal stipe distinct, white, K-, P-. Ascospores 13–17 × 6–8 µm. Pycnidia not seen.

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

Distribution and habitat:—Corticolous (especially on palm trees) in coastal forests up to 300 m in South and East Asia, Australia, Papua New Guinea, Philippines, Polynesia and Micronesia.

Notes:—This species is characterized by the white to yellowish white or yellowish grey upper surface with laminal, elevated, orbicular soralia, the orange to orange-red upper part of the medulla, a colourless stipe and the presence of atranorin and terpenes. Pyxine fallax is similar, but it has a uniformly white medulla, and it contains norstictic acid and testacein. For differences from P. daedalea see key.