Caloplaca squamuloisidiata van den Boom & V.J. Rico
Lichenologist, 38: 530, 2006.
Distribution: C - Sar (Herb. Vondrák nr. 9605).
Description: Thallus crustose, episubstratic, pale greenish grey or brownish grey, often with pale olivaceous patches, rimose-areolate to subsquamulose, isidiate, forming orbicular to irregular, marginally often sublobate patches, the lobules 0.5-0.7 x 0.2-0.3 mm, often surrounded by a pale to dark brown prothallus. Areoles 0.1-0.4(-0.5) mm wide, angular or rounded, often with upturned, wavy, incised margins; isidia simple to branched-coralloid, cylindrical to somehow flattened, 0.05-0.1(-0.15) x 0.1-0.5 mm. Upper cortex paraplectenchymatous, with a thin epinecral layer; algal layer mostly continuous; medulla poorly developed. Apothecia lecanorine/zeorine 0.2-0.8(-1) mm across, adnate to sessile and constricted at base, with a flat to weakly convex, orange, epruinose disc, and a paler, grey, smooth to granular-isidiate, often flexuous margin, which is usually persistent but tends to become thinner with age. Exciple paraplectenchymatous throughout, olivaceous to brownish in outer part, colourless within; epithecium orange to red-brown, granular, K+ red; hymenium colourless, 50-70 µm high; paraphyses simple or sparingly branched, 1.5-2.5 µm thick at mid-level, the apical cells up to 5 µm wide; hypothecium colourless, up to 50 µm high. Asci 8-spored, narrowly clavate, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, 9-14 x 5-8 µm, the septum 4-7 µm thick. Pycnidia frequent, immersed, pale to dark olive around the ostiole. Conidia short-bacilliform, 3-4.5(-5) x 0.8-1.2(-1.4) µm. Photobiont chlorococcoid. Spot tests: thallus K- or K+ violet, C-, KC-, P-; apothecial disc K+ red. Chemistry: thallus and proper margin of apothecia with the Sedifolia-grey pigment; apothecial disc with unidentified anthraquinones.
Note: a recently-described species, hitherto known from the Iberian Peninsula and Sardinia, characterised by a squamulose, isidate thallus. It grows on rather shaded, steeply inclined to underhanging surfaces of siliceous rocks. The sample from Sardegna was collected in the Gennargentu Massif near Fonni, on the northern slopes of Mt. Monte Spada, at c. 1450 m. According to Vondrák (in litt.) the species does not belong to Caloplaca s.str.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by isidia, or isidia-like structures (e.g. schizidia)