Pyxine berteriana (Fée) Imshaug, Trans. Amer. Microsc. Soc.

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 : 37-38

Pyxine berteriana (Fée) Imshaug, Trans. Amer. Microsc. Soc. 76: 254 (1957).

Type:— Circinaria berteriana Fée, Essai cryptog. écorces officin.: 128 (1825). Holotype:—Insula Martinicensi [ Martinique], ad corticem Quassiae excelsae (G!) — Pyxine meissneri Tuck. ex Nyl., Ann. Sci. Nat. ; Bot., sér. 4, 11: 205 (1859). Lectotype (selected by Imshaug 1957: 254):— Cuba, C. Wright, Wright, Lich. ins. Cubae exs. 95 ( FH!) = Pyxine cocoës var. meissneri (Tuck. ex Nyl.) Tuck., Proc. Amer. Acad. Arts Sci. 12: 166 (1877).— Pyxine meissneri var. rinodinoides Vain., Ann. Acad. Sci. Fenn. A (6): 69. Holotype:—[Lesser Antilles] Insula S. Jan, ad corticem arboris prope Coral-Bay (Caroline), 22 February 1906, Raunkiaer 443 (C, fide Jungbluth 2010).

Thallus corticolous, 5–9 cm wide, adnate to tightly adnate. Lobes radiating, discrete to ± contiguous, plane to convex, but often slightly concave towards the tips, 0.3–1.3 mm wide, subrotund at the apices. Upper surface white to light grey, greenish grey or yellow-grey, sparsely pruinose at the lobe tips (pruina punctiform) or epruinose; polysidiangia, isidia and soredia absent. Pseudocyphellae distinct, marginal and laminal, subreticulate. Medulla upper part: (pale) yellow, lower part: white. Lower surface black in the centre, paler towards the margin; rhizines ± dense, furcate. Apothecia common, cocoës - type, 0.5–2.0 mm wide; disc epruinose. Internal stipe distinct, white, K-, P-, C-, KC-. Ascospores 15–20 × 6–7 μm. Pycnidia rare, immersed in small warts on thallus with an exposed black ostiolum; conidia 4–5 × 1–1.1 µ m.

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

Distribution and habitat:—Pantropical and common in North, Central and South America, Africa, Australia, New Caledonia and the Galapagos Islands.

Notes:—This species is characterized by the presence of cortical lichexanthone, the absence of vegetative propagules, the yellow upper medulla (white below) and apothecia of the cocoës- type and a white internal stipe. It is often confused with P. australiensis ( Kalb 1994:61) , but that species has narrower lobes, a uniformly yellow medulla and apothecia of the obscurascens - type. Also similar is the Neotropical P. endolutea Kalb ( Kalb 1987: 49) , but this species is readily separated by the presence of atranorin (UV-). Although this species has not yet been reported for Thailand, we have added a description for convenience. Most of the herbarium material which was labelled P. berteriana was revised to P. cognata which is easily separated by its orange medulla (upper part) and obscurascens - type apothecia.