Diorygma isabellinum (Zahlbr.) Z.F. Jia & Luecking

Jia, Ze-Feng & Luecking, Robert, 2017, Resolving the species of the lichen genus Graphina Muell. Arg. in China, with some new combinations, MycoKeys 25, pp. 13-29 : 23-24

2. Diorygma isabellinum (Zahlbr.) Z.F. Jia & Luecking comb. nov.

Graphina isabellina Bas.: Zahlbr., in Handel-Mazzetti, Symb. Sin. 3: 58, 1930; Type: China (Hunan), Handel-Mazzetti 11437 (holotype W!).

Description.

Thallus corticolous, crustose, surface milk-white, somewhat yellowish, warty and rough; apothecia lirelliform, elongate, single and rarely branched, 2-4.5 mm long and 0.2-0.35 mm wide; labia obvious; discs closed to slightly opened; proper margin conspicuous, concolorous with the thallus; proper exciple not carbonized; hymenium clear, 160-180 µm high. I–; 1 ascospore per ascus, hyaline, ellipsoid, muriform, I+ violet, 110-120 × 35-48 µm.

Chemistry.

Norstictic acid (major), connorstictic acid (minor or trace).

Notes.

Because of the characteristics of thallus, lirellae and ascospores, this species belongs to Diorygma and is here recombined as D. isabellinum (Zahlbr.) Z.F. Jia & Lücking. It is similar to D. pachygraphum , but differs by smaller ascospores, the latter having ascospores 170-250 × 42-58 µm; it also similar to D. junghuhnii (Mont. & Bosch) Kalb, Staiger & Elix, but the latter differs in a I+ blue-violet hymenium and and smaller ascospores (60 –)80– 125 × 21-42 mm ( Kalb et al. 2004). In the recent world key to Diorygma ( Feuerstein et al. 2014), this species would key out at couplet 41.