Lecania graminum (Vain.) J. Gerasimova & S. Ekman, 2017

Gerasimova, Julia V. & Ekman, Stefan, 2017, Taxonomy and nomenclature of seven names in Bacidia (Ramalinaceae, Lecanorales) described from Russia, Phytotaxa 316 (3), pp. 292-296 : 293-294

Lecania graminum (Vain.) J. Gerasimova & S. Ekman , comb. nov.

MycoBank no.: MB820741

Lecidea graminum Vain. (1909: 103) . Bacidia graminum (Vain.) Zahlbr. (1926b: 203) . Type:— RUSSIA. Chukotka Peninsula: “Sibiria: Peninsula Jinretlen. 67° lat. bor., 173° long. occid. (Greenw.)”, 1878, E. Almquist s. n. (lectotype, designated here: S L32117!; isolectotype: TUR-V 20778 !).

Lecania graminum , like Lecidea alborussula , was described from the Chukotka Peninsula, where it was collected on decaying plant debris, seemingly on sandy soil. Its thallus appears whitish (but may have been discoloured by age) and encrusts the substrate by forming coalescing irregular granules. Apothecia are abundant, brownish yellow to more or less brown to black, often piebald, soon becoming strongly convex, 0.4–0.75 mm diam. The proper exciple is poorly developed, paraplechtenchymatous, visible as a thin rim in young apothecia but soon excluded. Excipular hyphae are moderately gelatinized and have narrowly to widely ellipsoidal cell lumina that become up to c. 20 μm long and are strongly constricted at the septa. The hypothecium and medulla are poorly differentiated and form a strongly developed cushion of hyphae. The hymenium is 35–40 μm thick, containing clavate, stout (3–4 μm wide at half their length), unbranched paraphyses with apices up to 6 μm wide and clavate asci with 8 or more helically arranged ascospores (possibly 12 or 16, difficult to count; our highest count is 14 clearly visible ascospores). Ascospores are acicular 27–41 × 2.0–2.5 μm (28–41 × 2.0 μm according to Vainio 1909), mostly with 4 thin septa. The upper part of the hymenium and proper exciple are often diffusely coloured by a brown, K+ purplish pigment; all other parts of the apothecium are unpigmented.

Lecania graminum is externally similar and apparently closely related to Lecania subfuscula (Nyl.) S. Ekman , but differs primarily in the longer and narrower acicular spores and by occasionally forming more than 8 ascospores per ascus. The similarity with L. subfuscula was pointed out by Vainio in his description (1909). Another close relative of L. subfuscula , named L. granulata Coppins & Fryday , was recently described from Scotland ( Fryday & Coppins 2012). It differs from L. subfuscula primarily in the crenulate thalline margin in young apothecia.