Buellia spuria (Schaer.) Anzi. (1860:87) (Fig. 5)

Basionym: Lecidea spuria Schaer., Lich. Helvet. Spicil. Sect. 3: 127 (1828)

Type:— SWITZERLAND. Kanton Zürich. On granitic alpine boulders growing with Lecidea atro-alba [original label data: Ad saxa granitica, Schleicher, 1823 sub Lecidea atro-alba; Hepp, Flechten Europas Nr. 33, auf Alpenfindlingen bei Zürich], collected by Schleicher s.n., distributed by Hepp, Lich. Helvet. Exs. 33, 0023903 (isoneotype M [photo!]); 000660170 (isoneotype BM [photo!]).

For further synonymy, see Bungartz et al. (2004, 2007).

Thallus saxicolous, crustose, thin to moderately thickened, continuous, epilithic; areolate; prothallus conspicuously black, visible between areoles, rarely only surrounding thallus outline; surface matt, usually white to whitish grey, rarely dark grey, epruinose, phenocorticate; medulla white, I+ blue, lacking calcium oxalate (H 2 SO 4 –).

Apothecia lecideine, sessile, numerous, immersed to adnate, round 0.3–0.5 mm in diam.; disc epruinose, black, rarely becoming slightly convex with age; proper margin thin, persistent, rarely excluded with age, black or color masked by greyish necrotic thalline material; exciple narrow aethalea - type (Bungartz et al. 2007), aeruginose pigments continuous with epihymenium (K–, HNO ₃+ violet); hymenium, hyaline, not inspersed, 50–60 µm high; paraphyses simple to moderately branched, apically swollen, with brown pigment cap and diffuse, aeruginose pigment (K–, HNO 3 + violet). Asci 8-spored, clavate, Bacidia - type. Ascospores olive to brown at maturity, oblong to ellipsoid, Buellia - type, proper septum and spore wall thin, not thickening during spore ontogeny, ornamentation absent, (9.4–)10.5–13.9(– 15.3) × (4.8–)5.6–6.8(–7.4) µm, l/w= (1.7–)1.8–2.1(–2.4) (n = 30).

Pycnidia not observed.

Chemistry: Spot test: K+ yellow to red (forming crystals), P+ yellow, C–, KC–. Thallus UV –. TLC: atranorin (major), norstictic (major) and connorstictic acid (minor).

Distribution: This is cosmopolitan species found in the Northern Hemisphere (Bungartz & Nash 2004a), southern and eastern hemisphere (Joshi et al. 2010, McCarthy 2023) on a variety of siliceous rock. In India it is distributed in tropical to subtropical regions between elevation 500 to 1600 m and found growing along with species of Aspicilia and Lecanora.

Notes: Buellia spuria is closely related to B. stellulata (Taylor in Mackay 1836:118) Mudd (1861:216). which shares similar morphological characters, but latter species consistently has a non-amyloid medulla and lacks norstictic acid (Bungartz et al. 2007). The description provided here is based on Indian specimens which matches well with protologue and the isoneotype photos of Buellia spuria.

Specimens examined: INDIA. Himachal Pradesh, Beas River valley, Kulu, on way to Barahi road, elev. ca. 1500 m. 16 June 1975. D.D. Awasthi & K. Dange 75032 A (LWG-LWU). Karnataka, Chikmangalure district Chikmagalure to Kummangundi, on rock, elev. 1100 m. 01 May 1979. D. D. Awasthi, D.K. Upreti & U. Mishra 79.417 (LWG-LWU). Manipur, Ukhrul, on rock, elev. 1676 m. 05 November 1976. K.P. Singh 55186 (LWG-LWU). Odisha, Ganjam district, on way to Seranga, on rock. 03 March 1986. D.D. Awasthi, G. Awasthi, R. Mathur & P. Srivastava 86.158 (LWG-LWU). Tamil Nadu, Salem district, Palamalai Hills, elev. 705 m. N11°44’10.4”, E77°44’29”. 14 February 2012. Logesh, Komal & Preeti 12-028076 (LWG); Nilgiri Hills, Love dale, on rock. 01 December 1973. K.P. Singh 73.515 (LWG-LWU). Uttarakhand, Almora district, Almora, Karbala, Pine Forest, on exposed rock, elev. 1600 m. 26 May 1997. D.K. Upreti, Chatterjee & Tandon L69762, L69761 /B (LWG); Jim Corbett Tiger Reserve, Sandikhal, on rock, elev. 1000–1100 m. 03 December 1999. D.K. Upreti & Tandon 217429/A (LWG).