Pannaria elixii

Detailed description

Thallus orbicular to irregularly spreading, 2–6(–10) cm diam., closely attached, without a marginal projecting prothallus. Lobes narrow, 1–2 mm wide, flabellate–cuneate, rarely discrete to contiguous to imbricate at margins, complex–imbricate centrally, concave at margins to plane or convex. Margins rounded, ±shallowly incised or crenate, often white-tomentose or occasionally ±blackened, noticeably thickened below, becoming densely isidiate towards centre. Upper surface pale to dark grey-blue when wet, marginal areas yellow-grey when dry; minutely granular or leprose–scabrid (×10 lens) at margins, smooth subrugose or ridged, often strongly plicate–wrinkled and densely isidiate centrally. Isidia terete, simple, 0.1 mm diam., or less, granular at first becoming gnarled glomerulate, friable, bluish white or greyish, marginal and on interlobe ridges to occasionally scattered on upper surface or densely crowded–congested and forming a diffract–areolate crust centrally, often ±obscuring entire thallus. Lower surface pale-buff or whitish in a narrow marginal zone, red-brown to black centrally and short-tomentose at margins with tufts of short brownish to black, squarrose rhizohyphae towards centre. Apothecia occasional to rare, often absent, sessile, laminal, rounded to 1.5 mm diam., often obscured by and/or sunk within dense isidiate crust; disc red-brown, matt, proper exciple obscured by persistent, densely isidiate thalline exciple. Ascospores 10–15 × 5–8 μm, with wrinkled perispore.

Chemistry: Pd+ yellow-orange; containing vicanicin, norvicanicin and rarely leprolomin and terpenoids; occasionally Pd− (no compounds).