Dimelaena oreina (Ach.) Norman (1852: 231) MycoBank

Ai, Min, Zhong, Qiuyi, Scheidegger, Christoph, Wang, Lisong & Wang, Xinyu, 2022, Revision of Dimelaena Norman (Caliciaceae, Ascomycota) species containing usnic acid reveals a new species and a new combination from China, Phytotaxa 574 (4), pp. 259-272 : 266-268

Dimelaena oreina (Ach.) Norman (1852: 231) MycoBank no. 384375

Lecanora straminea var. oreina Acharius (1810: 432) .

Type:— SWITZERLAND. ‘In alpibus Helvetiae’, Schleicher, 1018A (H-ACH, lectotype!) .

For further synonyms see Sheard & Ahti (1975).

( Fig. 4 )

Thallus crustose, thick or thin, loosely attached to the substrate, areolate at center and radiate-plicate at margin, areolae large, up to 2.00 mm long, 1.15 mm wide, irregular in shape, usually darkened around the areolae and surface margin; marginal lobes narrow, <2.00 mm long, c. 1.50 mm wide, thick, convex and usually darkened around the tips; thallus yellowish green with usnic acid in cortex but sometimes lighter to pale yellowish white, medulla white, without the lower cortex.

Apothecia cryptolecanorine to lecanorine, innate to adnate, often touching each other, roundish, 0.18–1.20 mm in diam., disc black, disc margin concolorous with thallus; epihymenium brown; hymenium hyaline, 80–100 μm high, inspersed with oil droplets; hypothecium hyaline, 80–125 μm high; asci clavate, Bacidia - type, 8-spored; ascospores brown, 1-septate, thin walled, 8.5–13 × 4.5–7 μm, markedly constricted at septum when mature.

Pycnidia numerous, immersed; conidia bacilliform, 3–6 × 0.7–1 μm.

Chemistry: Usnic and gyrophoric acids, occasionally with stictic acid in our examined specimens from China.

Ecology and distribution: This species usually grows on exposed siliceous rock, at elevations of 2798–3942 m. Distributed in North America, South America (rare), Europe, Asia and South Africa (rare) ( Sheard & Ahti 1975, Mayrhofer et al. 1996).

Notes: Dimelaena oreina is the type species of Dimelaena . One specimen from Switzerland (where D. oreina was originally described) has a newly generated molecular profile to confirm the phylogenetic position of the genus Dimelaena . Specimens of D. oreina from China cluster with those from Europe in the phylogenetic tree. Furthermore, the specimens in this clade contain gyrophoric acid, which is consistent with spot test results from the type specimen (K–; KC–). The species still needs further study by molecular and chemical analysis including all the five chemotypes from Europe.

Additional specimens examined. CHINA. Gansu Province: Subei Co., Nanshan Mt., near 29th Mengke Glacier , 3942 m, 39°12′42.51″N, 95°23′00.50″E, 23 May 2018, Wang Lisong et al. 18-59460; Subei Co. , Nanshan Mt. , near 29th Mengke Glacier, 3909 m, 39°12′43.08″N, 95°22′59.77″E, 23 May 2018, Wang Lisong et al. 18-59432; Subei Co. , Nanshan Mt. , near 29th Mengke Glacier, 3942 m, 39°12′43.93″N, 95°23′00.32″E, 23 May 2018, Wang Lisong et al. 18-59450; Subei Co. , Nanshan Mt. , near 29th Mengke Glacier, 3885 m, 39°12′40.74″N, 95°23′03.95″E, 23 May 2018, Wang Lisong et al. 18-58504; Sunan Co. , on the route from Sunan to Qilian, 3492 m, 38°39′16.51″N, 99°29′29.16″E, 30 May 2018, Wang Lisong et al. 18-58843; Yumen Ci., Yuerhong Vil., 3332 m, 39°38′13.77″N, 97°09′15.57″E, 27 May 2018, Wang Lisong et al. 18-58641; Yumen Ci., Yuerhong Vil., 3291 m, 39°38′14.84″N, 97°09′15.94″E, 27 May 2018, Wang Lisong et al. 18-59552 . Qinghai Province: Huangyuan Co., rocky slope beside G315, 2798 m, 36°46′53.65″N, 101°07′21.77″E, 18 May 2018, Wang Lisong et al. 18-58134 .

Figures

FIGURE 4. Morphology and anatomy of Dimelaena oreina (18-59460, KUN). A. Thallus of Dimelaena oreina. B. Convex non-linear lobes of radiate-plicate margin. C. Cryptolecanorine apothecia. D. Darkened margin around the areolae. E. Section of apothecium. F. Buellia-type ascospores, constricted at septum. G. Typical Bacidia-type ascus-apex. Scale bars: 1 mm (A, B); 0.5 mm (C, D); 25 μm (E); 5 μm (F, G).