Sticta squamata

Detailed description

Thallus foliose, lobate, spreading, broadly attached, 5-10(-22) cm diam., thin and fragile, papery, to thick and coriaceous. Lobes 3-8(-12) mm wide, loosely subdichotomously branching near periphery, more complex-imbricate centrally, margins ± subascendent, rarely entire, crisped, somewhat thickened, often tinged brownish, ± densely isidiate. Upper surface smooth, matt, ± coriaceous, ± wrinkled-plicate in parts, bright lettuce-green when wet, superficially browned at margins or sometimes over whole thallus, pale greenish- buff when dry, isidiate. Isidia short, 0.1-0.3(-1.2) mm tall, c. 0.1 mm wide, squamiform-imbricate, ± flattened to erect, marginal at first in well-defined lines, often dense, spreading to lamina and sometimes forming a dense, diffract, fragile crust centrally. Lower surface pale buff or whitish or pinkish to pale or dark brown centrally, tomentose, tomentum regular, to margins, or only ± central with patches of shining, irregularly, pitted or wrinkled lower cortex at margins. Cyphellae 0.1-1.2 mm diam., rounded to subirregular, white. Apothecia rare, 1-3.5 mm diam., scattered, sessile to subpedicellate, disc bright orange or orange-yellow, waxy, concave at first and then often obscured by inrolled margins, plane to subconvex-undulate at maturity, margins persistent, thick, crenate, pale buff or whitish, exciple pale buff or red-brown, corrugate- scabrid, ± translucent when wet. Epithecium pale brownish-yellow, 8-13 µm thick. Hymenium 130-155 µm tall, colourless. Paraphyses moniliform, apices capitate. Ascospores biseriate, elongate-ellipsoid with pointed apices, 3-septate at maturity, 27-37 × 6.8-8.3 µm.

It may also occasionally be infected with galls of the lichenicolous fungi *Plectocarpon sticticola and *Unguiculariopsis triregia.