TYPE. AUSTRALIA. Tasmania, Pelion Plains, 1 km W of Pelion Hut, 41°50' S 146°02'E, 890 m altitude, on eucalypt stump in Eucalyptus delegatensis open forest, 11.III.1992, G. Kantvilas 267/92 (HO, holotype; BM, isotype).
Life form. Lichenized fungus.
Description. [modified from Kantvilas (2009)] Thallus morphology: crustose, whitish, continuous, waxy, smooth to verruculose, often becoming cracked and areolate, 120–250 µm thick; vegetative diaspores absent. Thallus anatomy: ecorticate; medulla white except occasionally with discrete specks of a red pigment beneath the apothecia, K+ intensifying orange-red, N+ orange-yellow and slowly dissolving. Photobiont chlorococcoid alga; cells globose, 5-11 μm diam.
Ascomata biatorine apothecia, scattered, roundish, 0.5-2.0 mm diam., occastionally fused in clusters to 3 mm wide, superficial, usually adnate; disk black, strongly convex; margin indistinct. Exciple excluded at first to ~40 µm thick, cinereorufa-green, composed of a reticulum of short-celled hyphae, typically with adhering thalline tissue. Hypothecium 60-160 µm thick, hyaline, sparsely inspersed with oil droplets 6-8(-15) µm diam. and minute POL+ bluish crystals that dissolve in K, subtended by a pale, straw-colored subhypothecium intensifying in K, N-, sometimes with cinereorufa-green pigment. Hymenium 110-160 µm, hyaline, sparsely inspersed; epihymenium dark cinereorufa-green. Paraphyses numerous, conglutinate, branched and anastomosing, 1.5-2 µm thick, tips somewhat expanded to 3-4 µm and pigmented. Asci elongate-clavate, 110-130 µm, 1-spored; ascospores broadly ellipsoid to ± oblong, simple, hyaline, (60-) 64-93.1-104 x 28-46.1-52(-55) µm; wall 5-12 µm thick, 2-layered. Conidiomata pycnidia, scattered, immersed, minute, black; conidia bacilliform, 6-8 x 1 µm.
Chemistry. UV-, K+ faint yellow, KC-, C-, PD-; atronorin and caperatic acid detected by TLC .
Substrate and habitat. Corticolous on hardwood trees in moist mesic forests.
Distribution. Australasia, east Asia, scattered throughout North America (Alaska, Pacific Northwest, eastern North America from Canadian Maritimes down along Appalachian mountains; in North Carolina found in the Blue Ridge ecoregion.
Note. This species is distinguished from M. sanguinarius by its thicker thallus, occasional red pigment that turns brown and fades in herbarium specimens, and presence of caperatic acid.
Literature
Kantvilas, G. (2009) The genus Mycoblastus in the cool temperate Southern Hemisphere, with special reference to Tasmania. The Lichenologist41(2): 151-178.