Lepraria caesioalba var. groenlandica L. Saag
Nomenclatural data
MycoBank — MB 510911
Thallus leprosus, granulosus, similis Leprariae caesioalbae var. caesioalbae. Atranorinum, zeorinum et acidum sticticum continens.
TYPUS: Greenland. Qaanaaq, Thule, alt. (77°29'N, 69°12'W), soil (humus) and mosses, 28 June 1986 E. S. Hansen ESH-86.0321 (C – holotypus, TU – isotypus; atranorin, zeorin, rangiformic acid, stictic acid, constictic acid (trace)).
Crustose, leprose, with granular appearance, thick and hard, rarely thin and/or somewhat softer; usually dark grey, sometimes light grey to almost white, mostly with bluish (“cold”) tinge; securely attached to the substrate, sometimes growing in irregular patches up to several cm in diam., often young thalli forming smaller rosettes with concentric zones often visible; thallus margin diffuse or often delimited and with obscure sublobes or rim; medulla sometimes present, not evident; soredia variably sized, mostly coarse, 100–150(–200) µm in diam., often pruinose, rarely with short projecting hyphae; consoredia frequent, typically 200–300 µm in diam, convex or ellipsoidal.
L. caesioalba var. groenlandica differs from the stictic acid chemotypes of L. caesioalba var. caesioalba by producing zeorin. Three chemotypes are recorded in Greenland: (1) with atranorin, zeorin, the stictic acid complex and roccellic/angardianic acid (n = 4); (2) with atranorin, zeorin, the stictic acid complex and rangiformic acid (n = 1); (3) with atranorin, zeorin and the stictic acid complex only (n = 1).
Lepraria caesioalba var. groenlandica is described here on the level of variety because it does not differ morphologically from L. caesioalba var. caesioalba. Chemically this new variety is similar to L. elobata which is morphologically different in the following aspects: L. elobata has thin powdery thallus composed of mostly fine soredia (consoredia are rare) and diffuse thallus margin, unlike the varieties of L. caesioalba. L. caesioalba may be a collective species (Ekman & Tønsberg 2002, Tønsberg 2004) but without comprehensive molecular study the separation on species level seems not justified.
Ecology and distribution

On soil and bryophytes, sometimes overgrowing other lichens.
L. caesioalba var. groenlandica is known only from Greenland. It is scattered across the Low Arctic, with one locality in the northwest of the High Arctic region.
Saag, L., Hansen, E. S., Saag, A. & Randlane, T. 2007.