Basionym: Lecanora floridana Tuck., Proc. Amer. Acad. Arts & Sci. 5: 402. 1862 [1860]; MB#388267.
Description. Thallus continuous to indistinctly rimose, small patches up to 2.5 cm in diam., effuse, but typically delimited by a radiating, ± fibrous black prothallus; surface deep blackish gray to olive gray, smooth, not shiny, epruinose, lacking vegetative propagules. Apothecia numerous, dispersed, sessile, up to 0.6 mm in diam., biatorine-lecideine (not or only very weakly carbonized), thalline margin absent, but when emerging occasionally covered in part by a thin thallus residue (‘thalline veil’); proper margin thin, ~60 μm thick, prominent, regularly circular, black, concolorous with the disc, epruinose; disc flat, becoming slightly convex with age, black, epruinose; epihymenium bluish black, pigmentation diffuse, C+ wine red, K+ violet, pigment granules absent, ± contiguous with the outer exciple; hymenium hyaline, not inspersed; proper exciple differentiated into an inner hyaline part, lacking crystals, and an outer part with a diffuse bluish black pigment, C+ wine red, K+ violet; subhymenium and hypothecium not differentiated, hyaline, not inspersed; asci clavate, Teloschistes-type; ascospores 8/ascus, polaribilocular, spores narrowly ellipsoid to weakly citriform (moderately tapering), (10.7–)12.1–14.9(–16.5) × (5.1–)5.7–7.0(–8.5) μm, with a thick, (3.9–)4.8–6.8(–8.6) μm wide septum (n = 50). Pycnidia unknown.
Chemistry. Thallus and apothecia P–, K–, C–, KC–, UV– (dull); no secondary metabolites detected.
Ecology and distribution. Presumably widely distributed in dry habitats of the Neotropics. Tuckerman (1862) originally described the species from Florida (USA), Tucker (1979), subsequently reported it from Lousiana (USA), Wetmore (2007a) from Sinaloa (Mexico), suggesting it may be restricted to North America, even though Weber (1986) had already reported it from the Galapagos. There, the species occurs from the coastal throughout the dry into the lower transition zone. In Galapagos, the species has so far only been found on Bursera graveolens, typically on sunny, wind- and rain-exposed trunks, branches and twigs.
Notes. The only other Teloschistaceae species with blackened apothecia in the Galapagos is the saxicolous Caloplaca nigra (differences discussed there). Caloplaca floridana is represented here by three ITS sequences that are very uniform and well separated from all other species.
Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2007. Lichen Flora of the Greater Sonoran Desert Region. Vol 3.
Life habit: lichenized Thallus: crustose, continuous, without elongated lobes; prothallus: present, black surface: gray, smooth, without asexual propagules Apothecia: adnate, 0.2-0.4 mm in diam., lecanorine disc: dark brown or black, flat, epruinose margin: persistent, flush or slightly raised; thalline margin present, concolorous with thallus; proper margin visible, concolorous with disc parathecium: elongate to oval cells; exciple below hypothecium irregular hyphae epihymenium: brown or gray, K+ violet, 10%N + violet, cN+ violet hymenium: hyaline, 60-85 µm tall paraphyses: 1-2 tip cells slightly swollen, with few branches; subhymenium hyaline asci: cylindrical, 8-spored ascospores: hyaline, 2 locules, ellipsoid, 11-14 x 5.5-7 µm, isthmus (4-)5.5-7(-8.5) µm, spore end wall thin Pycnidia: not observed Spot tests: apothecial margin K+ violet, 10% N+ violet, cN+ violet, C-; thallus K-, 10%N-, cN- Secondary metabolites: thalloidima green. Substrate and ecology: on bark World distribution: North America Sonoran distribution: northern Sinaloa. Notes: Caloplaca floridana has a thin gray thallus and usually a black prothallus:. The epihymenium is K+ violet in contrast with C. diphasia that has a K+ yellow epihymenium.