Arthonia ochraceella Nyl.

Broeck, Dries Van Den & Ertz, Damien, 2018, Enterographa confusa sp. nov. (Roccellaceae, Arthoniales) discovered by chance in type material of its host lichen Arthonia ochraceella, described more than a century ago, Phytotaxa 343 (1), pp. 89-93 : 92

Arthonia ochraceella Nyl. ex. Willey

Synopsis of the genus Arthonia : 10 (1890)

Type: — CUBA. C. Wright, #Graphid. Cub. 121c (lectotype G!, here designated; barcode G00290277)

Thallus corticolous, crustose, greenish white, discontinuous, thin, the periderm ± visible through the thallus, in section ca. 3–10 μm thick, largely endophloeodal; UV ± pale orange with white to yellowish patches; thallus hyphae and prothallus not observed. Photobiont trentepohlioid, cells 8–13 × 7–12 μm, rounded, solitary or in short chains. Ascomata rounded to lirelliform to stellate, immersed, irregularly spread on the thallus, emarginate, numerous, 0.2–1.4 × 0.07–0.1 mm; in section 85–100 μm thick; disc brown, epruinose, translucent, wet orange and transparent, flat to concave; calcium oxalate crystals absent. Excipulum inconspicuous. Epihymenium yellowish, 20–25 μm, composed of intermingled tips of paraphysoids, I– to I+ orange. Hymenium hyaline to slightly yellowish, 45–55 μm, strongly conglutinated; hymenial gel I+ blue, KI+ blue. Subhymenium yellowish, c. 16–18 μm, not well separated from hymenium, gel I+ blue, KI+ blue. Paraphysoids richly branched and anastomosed, 1.7–2.2 μm, distinct, embedded in dense gelatinous matrix, hyaline, without dark walled tips or caps, ± parallel between the asci. Asci globose to broadly clavate, 2–6-spored; 40–54 × 36–45 μm (N = 4); a KI blue ring like structure in the tholus or an ocular chamber not observed; stipe not observed; walls thin, 0.6–1.5 μm; ascal gels I+ orange to red. Ascospores hyaline, ovoid, (3–)4(–5)-septate, with two enlarged end cells, 28–34 × 9.5–14.5 μm (N = 12), constricted at septa; spore ontogeny macrocephalic, unidirectional; gelatinous sheet hyaline, 1.0–2.5 μm in water. Conidiomata not seen.Thallus and ascomata K–, C–, KC–, PD –.

Distribution and ecology: —The species is only known from the type locality in Cuba, on bark.

Remarks:— The examined specimen of Arthonia ochraceella (Graphid. Cub. 121c, barcode G00290277) is selected as lectotype because two type specimens are present in G. The other one with barcode G00290276 is also infected by Enterographa confusa (photo present on JSTOR). The specimen G00290277 is well-developed and representative of the species. As stated by Müller (1894), Willey described the species and therefore we prefer to add « ex. Willey » as author of the species.