Pleopsidium discurrens (Zahlbr.) Obermayer

Ann. Bot. Fennici 33: 232 (1996).

Basionym: Acarospora discurrens Zahlbr. in Handel-Mazzetti, Symbolae Sinicae, Pars III: 140 - 141, fig. I. (1930).


Synonyms: Index Fungorum

Protolog: Data lacking.

Type locality: China, Prov. Yunnan, bor.-occid.: In montis Yülung-schan prope urbem Lidjiang ("Likiang") regione alpina, ad rupes inter pratum Latuka et alveum Schitako. Substr. schisto argilloso; 4000 m, 20.7.1914, H. Freiherr v. Handel-Mazzetti (WU - lectotype, W - isolectotype). Lectotypification by Obermayer (1996: 232).

Barcode: Available. Data lacking.

Coordinates: Data lacking.

Thallus: yellow, up to 7 cm in diameter, areoles ribbon-like elongated, marginally branched and spreading out (= 'discurrens'). Each radial arm (1 - 1.5 mm wide) can be followed almost from the center of the thallus. Tips of the areoles distinctly roughened, with deep tangential fissures towards the center of the thallus, which are caused by the fragility of the cortex. Structure of the cortex as described in Hafellner (1993: 285). Apothecia usually less than 1 mm in diameter, crowded within the center of the thallus, at least at the beginning with a distinct margin, becoming convex in the center and then margin partly disappearing. Disc of the fruiting bodies slightly darker than their thalline margin. Epithecium with yellow crystals. Hymenium colourless. Hypothecium colourless, with a cup-like tissue of adglutinate hyphe ('cupula') beneath. Paraphyses unbranched or with few branches at the level of the tips of the asci. Asci multispored, clavate, ascus-apex of the Pleopsidium/Candelariella type: tholus with a broad ocular chamber, surrounded by a cylinder that reacts blue with Lugol's iodine (see Hafellner 1993: 287 fig. 3). Spores colourless, narrowly ellipsoid to suboblong, 3.5 - 4 - 4.5 / 1.7 - 2 µm. Conidiomata immersed at the top of the areoles, wall of the conidiomata colourless. Conidigenous cells bottle-shaped (see Hafellner 1993: 289 fig. 6a). Conidia terminally tied off, ellipsoid to suboblong, 1.5 / 2.7 - 3 µm (Obermayer 1996: 232).

Photobiont: Trebouxioid green alga.

Chemistry: Rhizocarpic acid, acaranoic acid, acarenoic acid. If rhizocarpic acid is very concentrated, another compound (a second yellow tetronic acid?) also occurs frequently. See Obermayer 1994: 281 as pigment 'A1'.

Ecology: On overhanging silicious rock. 3600 - 4200 m.

Molecular data: Genbank

Distribution: Database