Pyxine hengduanensis 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 hengduanensis M. X. Yang & Li S. Wang sp. nov. Figure 3

Holotype.

CHINA, YUNNAN PROVINCE, Nujiang Pref., Dizhengdang Vil., 1858 m elevation, 28°05'00.86"N, 98°19'39.97"E, on bark, 2 Aug 2015, L. S. Wang et al. KUN-L 15-48082. GenBank accession No.: ITS = KY611889, mtSSU = KY751396.

Description.

Thallus corticolous, 4-9 cm wide, firmly to loosely adnate to substrate. Lobes linear, compact, imbricate to discrete, (0.5) 1-2.5 mm wide, upper cortex plane but often slightly concave towards the tips; pseudocyphellae linear, marginal; upper surface grey to greyish-green, lower-side black; rhizines dense, squarrosely branched. Soralia marginal, labriform; soredia grey to bluish-grey, powdery to granular. Medulla pale yellow. Dactyls and isidia absent. Apothecia absent. Upper cortex K+ yellowish, UV–; medulla K–, C–; containing chloroatranorin (minor) and unknown terpenes.

Habitat and distribution.

Growing on bark of Quercus and Alnus spp. Range 1700 -3060 m elevation in semi-arid environments; known only from Yunnan, Sichuan and Xizang in China.

Etymology.

The epithet hengduanensis refers to the type locality of the species, the Hengduan Mountains region.

Notes.

Pyxine hengduanensis is characterised by a corticolous habit, yellowish-grey to greyish-green thallus, marginal labriform soralia, pale yellow medulla and the absence of atranorin. Pyxine hengduanensis is most closely related to P. sorediata , as inferred from the phylogenetic tree (Fig. 1); P. sorediata is also corticolous but has a yellow or yellow-orange medulla and soralia that develop marginally from fissures and then become laminal and orbicular ( Elix 2009), while P. hengduanensis has marginal labriform soralia developing from the centre of the pseudocyphellae, grey to bluish-grey soredia and a pale yellow medulla. Pyxine hengduanensis also resembles P. retirugella Nyl. ( Elix 2009) in the marginal and laminal pseudocyphellae, but it differs in having white or creamy and K+ yellow turning red medulla and norstictic acid as the main compound ( Mongkolsuk et al. 2012).

Selected specimens examined (KUN).

CHINA: SICHUAN PROVINCE: Dukou Co., Yanbian Vil., Shibao Mt., 2900 m elev., 29 Jun 1983, L. S. Wang 83-635; Nanping Co., Jiuzhaigou, 2000 m elev., on Pinus , 23 Sep 1986, L. S. Wang 86-2591. XIZANG PROVINCE: Linzhi Co., 3060 m elev., 29°50'249"N, 94°44'728"E, on Quercus spp. 20 Aug 2007, L. S. Wang et al. 07-28389; YUNNAN PROVINCE: Luquan Co., 30 km from Sapanying Co. to Zehei Co., 2540 m elev., 26°04'24.53"N, 102°36'19.15"E, on moss, 19 Apr 2014, L. S. Wang et al. 14-43258; Lufeng Co., Heijin Vil., 1800 m elev., 25°20'146"N, 102°05'835"E, on bark, 1 May 2009, L. S. Wang 09-30247.