Graphis cerradensis Marcelli, Benatti & Lücking
Mycobank MB 517775
Thallus corticolous, up to 5 cm diam., 30–70 µm thick, continuous; surface smooth to uneven, matte, pale greenish grey; prothallus absent. Thallus in section with cartilaginous upper cortex, irregular algal layer and large clusters of crystals. Apothecia lirelliform, flexuose, unbranched to sparsely branched, prominent, with thick complete thalline margin, 1–3 mm long, 0.5–0.6 mm wide, 0.25–0.35 mm high; disc concealed; proper margin thick, labia striate; thalline margin thick, completely covering the labia, white. Excipulum apically crenulate, completely carbonized, 70–150 µm wide, black; laterally covered by corticate algiferous thallus including large clusters of crystals; hypothecium prosoplectenchymatous, 10–15 µm high, colourless to pale yellowish; hymenium 150–200 µm high, colourless, strongly inspersed with small granules along the paraphyses (paraphyses and asci hardly discernible), inspersion rapidly disappearing in KOH (type B); epithecium granulose, 10–15 µm high, olive brown. Paraphyses unbranched; asci fusiform to clavate, 130–180 x 30–40 µm. Ascospores 4–8 per ascus, oblong, muriform with 15–25 transverse and 1–3 longitudinal septa per segment, 80–100 x 15–20 µm, 6–7 times as long as wide, colourless. Secondary chemistry: stictic acid.
Graphis cerradensis belongs to the G. cinerea group, characterized by robust, prominent lirellae with often striate labia, massively carbonized excipulum, and strongly inspersed hymenium (Lücking, 2009; Lücking et al., 2008, 2009). Thus far, no stictic-acid containing species with muriform ascospores was known in this group. Most similar is G. argentata Lücking & Umaña, which lacks secondary substances and has slightly broader ascospores. Graphis inspersostictica Sipman & Lücking also appears to be closely related; it agrees with G. cerradensis in morphology and chemistry, but the lirellae are narrower with entire labia and the ascospores are transversely septate or very rarely provided with a longitudinal septum in one of the segments.
The epithet refers to the type of vegetation in which the species grows.
The new species is known from a single collection in a dense, humid Cerrado vegetation in southern Brazil.
Type:—BRAZIL. São Paulo: Mogi-Guaçu, Martinho Prado Jr., Mogi-Guaçu Biological Reserve; 22°15’S, 47°11’W; dense, humid Cerrado vegetation; on bark; Nov 2007, Lücking 23027 (holotype SP; isotype F).
Additional specimens examined (paratypes):—None.
Sicut Graphis inspersostictica sed ascosporis muriformibus differt.