Pyxine minuta Vain

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 minuta Vain

Description.

Pyxine minuta is characterised by narrow lobes, centrally subcrustaceous, saxicolous thalli, a whitish-grey or grey-brown upper surface; brownish-black lower surface with black and simple rhizines, a lack of isidia and soredia and a white or whitish stramineous medulla. Apothecia common, 0.5-1.5 mm wide; internal stipe absent or not distinct. Upper cortex K+ yellowish, UV+ yellow, medulla K–, C–; containing lichexanthone (major) and terpenoids (detected by TLC).

Habitat and distribution.

Growing on bark of Quercus spp. or rock around 1090-2230 m elevation in semi-arid environments. Worldwide distribution: India ( Awasthi 1982), Australia ( Rogers 1986) and newly recorded in China.

Notes.

There is some confusion in the classification of Pyxine minuta and P. pyxinoides . Pyxine minuta is characterised by narrow lobes, an absent or indistinct internal stipe, small spores (11-16 (18) × 5-7 μm) and a white medulla. Based on the world key to Pyxine species with lichexanthone ( Aptroot et al. 2014; Kalb 1987; Huneck et al. 1987), the characteristics of Pyxine pyxinoides are: Thallus without isidia, pustules or soredia, usually with apothecia; Medulla yellow, ochraceous or salmon; apothecium margin black, not thalline; apothecium without a clear stipe; one TLC run of a portion of the thallus without apothecia showed traces of a substance running like norstictic acid ( Obermayer and Kalb 2010); neotropical. We did not find any specimens of P. pyxinoides in our collections.

Selected specimens examined (KUN).

CHINA: SICHUAN PROVINCE: Dukou Co., Dabaoding, 1950 m elev., 21 Jun 1983, L. S. Wang 83-206. YUNNAN PROVINCE: Yongsheng Co., Shawan village of Renhe town, 1160 m elev., 26°19.449'N, 101°05.200'E, on rock, 7 Dec 2013, L. S. Wang et al. 13-40630, 13-40695; Yongren Co., Lagu village, 1050 m elev., 26°23.239'N, 101°25.120'E, on rock, 4 Dec 2013, L. S. Wang et al. 13-41380; Jinggu Co., on the way to Zhenyuan, 1800 m elev., 21 Aug 1994, L. S. Wang et al. 94-14247.