Sochting U, Lorentsen LB, Arup U. 2008. The lichen genus Caloplaca (Ascomycota, Lecanoromycetes) on Svalbard. Notes and additions. Nova Hedwigia 87(1-2): 69-96.
Thallus endo- or episubstratic on host lichen, very small, indistinct or composed of scattered areoles, margin simple or very weakly effigurate, well delimited; surface carmine red, smooth, matt, epruinose. Apothecia sparse, in loose groups, on host thallus or on areoles, orbicular, to 0.8 mm in diam., small, sessile, seem to grow somewhat skew, slightly constricted at the base, lecanorine, biatorine or zeorine; disc plane to weakly convex, carmine red with an orange tinge, surface structure smooth; apothecial margin first prominent to distinct, initially thick becoming thinner, persistent, not flexuose or occasionally flexuose, concolourous with remaining thallus surface, carmine red, slightly darker than disc, smooth. Excipulum to 60-100 μm wide, with few or no algal cells; proper exciple broad and prosoplectenchymatous, strongly glutinized, hyaline. Hypothecium hyaline, oil droplets present; subhymenium hyaline. Hymenium 50-60 μm high, hyaline; paraphyses ramifications scarce; terminal cells are swollen, to 7 μm wide, hyaline; subterminal cells to 3 μm wide; epihymenium 15 μm high, distinct, orange. Asci 52 × 13 μm. Ascospores c. 8 per ascus, ellipsoid, 9-11 × 5-6 μm; spore septum 2-3 μm.
SECONDARY METABOLITES: emodin, fallacinal, parietin, parietinic acid, and teloschistin; chemosyndrome A. All yellow parts K+ red, C-.
SUBSTRATE AND ECOLOGY: parasitic on lichens (see also notes). Habitat exposed to sun or partially shaded, dry.
NOTES: The strong carmine-orange pigmentation is only known from few Northern Caloplaca species, viz.: C. luteominia var. bolanderi (Tuck.) Arup, C. anchonphoeniceon Poelt & Clauzade and C. coccinea (Müll.Arg.) Poelt. C. luteominia var. bolanderi is not a possibility mainly because it has grey to beige thallus (Arup1993). The specimen from Svalbard was earlier identified to C. anchon-phoeniceon by Søchting and Olech (1995). However, the broadly sessile apothecia and the larger spores of C. anchon-phoeniceon is not characteristic of our specimen, so C. coccinea is the most likely identity, even though Hansen et al. (1987) note that C. coccinea is autotrophic on calciferous rock.
The Svalbard material (Søchting 5853 and Søchting 6177) was compared with Caloplaca coccinea from the Austrian Alps (Søchting 9340). The Austrian material differs from the Svalbard collection mainly in thallus morphology. The specimens from Svalbard are distinctly lichenicolous and have no visible thallus except some small scattered areoles. Though the Austrian specimen lives mostly directly on the rock and has an indistinct endosubstratic thallus that stains the rock pale rose, some apothecia resembles the Svalbard specimens and are lichenicolous. There are no obvious anatomical and morphological differences between the apothecia in the three collections.