Pyxine flavicans M. X. Yang & Li S. Wang

Yang, Mei-Xia, Wang, Xin-Yu, Liu, Dong, Zhang, Yan-Yun, Li, Li-Juan, Yin, An-Cheng, Scheidegger, Christoph & Wang, Li-Song, 2019, New species and records of Pyxine (Caliciaceae) in China, MycoKeys 45, pp. 93-109 : 93

Pyxine flavicans M. X. Yang & Li S. Wang sp. nov. Figure 2

Holotype.

CHINA, YUNNAN PROVINCE, Nujiang Perf., Chide Vil., 1916 m elevation, 27°42'32"N, 98°43'19"E, on Juglans , 4 Aug 2015, L. S. Wang et al. KUN-L15-48196. GenBank accession No.: ITS = KY611884, mtSSU = KY751391.

Description.

Thallus 5-9 cm wide, attached to closely adnate. Lobes radiating, plane to convex, but often slightly concave towards the tips, (0.5) 1-3 (4) mm wide, subround at the apices. Upper surface white-grey to celadon, sparsely pruinose at the lobe tips or epruinose, isidia and soredia absent. Medulla pale yellow above, white below. Lower surface black in the centre, paler towards the margin; rhizines dense, furcate. Apothecia common, (0.5) 0.8-1.5 (2) mm wide, constricted at base, plane to possibly convex; margin black. Hymenium height 80-120 μm; hypothecium light brown to brown, internal stipe K– pale yellow to yellow; spores brown, two-celled, 18-20 × 6-8 μm. Upper cortex K+ yellowish, UV–; medulla K–, C–; containing atranorin, chloroatranorin (minor), zeorin and unknown terpenes.

Habitat and distribution.

Growing on bark of Quercus and Picea spp. and on rocks around 1916-4000 m elevation in semi-arid environments; only known from south-western China.

Etymology.

The epithet flavicans refers to the yellow medulla and internal stipe of the apothecia.

Notes.

Pyxine flavicans is characterised by flat corticated yellowish-grey to brownish-grey thalli, a constricted base, a pale yellow medulla and the presence of atranorin.

This species resembles P. berteriana in terms of lobe size, saxicolous habitat and internal stipe, but the latter has a yellow to yellowish-orange medulla and produces lichexanthone ( Hu and Chen 2003). Pyxine flavicans is similar to P. australiensis Kalb regarding the absence of soredia and isidia and both species are frequently lignicolous but occasionally grow on rocks. However, P. flavicans differs from P. australiensis in having marginal and laminal pseudocyphellae, lichexanthone and a white medulla in the stipe ( Elix 2009). Pyxine flavicans is similar to P. himalayensis in terms of the type of apothecia and lack of lichexanthone. However, P. himalayensis has a colourless internal stipe.

Selected specimens examined (KUN).

CHINA: SICHUAN PROVINCE: Muli Co., 2850 m elev., on Pinus yunnanensis , 23 Aug 1983, L. S. Wang 83-1869(A); XIZANG PROVINCE: Chayu Co., along the road from Muruo Vil. to Bingzhongluo, 3833 m elev., 28°35.781'N, 98°06.404'E, on Pinus armandii , 26 Sep 2014, L. S. Wang et al. 14-46763; YUNNAN PROVINCE: Jianchuan Co., Shibao Mt., 2620 m elev., 26°22.920'N, 99°49.811'E, on bark, 24 Jun 2014, L. S. Wang et al. 14-43995; Nujiang Co., Chide Vil., 1916 m elev., 27°42'32.40"N, 98°43'18.59"E, on Juglans , 4 Aug 2015, L. S. Wang et al. 15-48196.