Thallus: whitish to pale buff, densely granular-blastidiate, to 1.5 mm thick; granules 30–80(–100) µm diam. Photobiont chlorococcoid, cells 5–12 µm diam or ellipsoidal to 14 x 12 µm in size.
Anamorph: not known.
Teleomorph: ascomata apothecia, (200–)300–700 µm diam, flat or becoming convex and then up to 900 µm diam, each developing within a thalline wart and becoming urceolate with a crenulate thalline margin and concave disc, later expanding further with the thalline margin becoming granulate or receding to reveal a proper margin, and with the disc becoming plane to convex. Disc pale, pinkish or pallid, often with patchy brown pigment towards the margin in older apothecia, with paler proper margin. Thalline exciple ca 40–60 µm wide. Proper exciple lateral to hymenium 35–60 µm wide, but not clearly delimited from hypothecium below, hyaline or dilute reddish brown, in outer half composed of ± radiating hyphae with lumina to 5 x 2.5 µm, cortical cells ca 5–6 µm diam. Hymenium 50–65 µm tall, hyaline or tinged dilute reddish brown in part in older apothecia; epihymenium hyaline or with patchy dilute reddish brown pigment, especially towards the margin; subhymenium 20–35 µm tall, K+ dilute yellow, with cells of ascogenous hyphae to 5 µm diam. Hypothecium massive, of irregularly orientated, slender hyphae ca 10–17 µm wide. Interascal tissue of simple paraphyses, ca 1.5 µm diam in mid-hymenium, the upper 2–4 cells gradually widening to 4(–6) µm diam, ± lax in K. Asci 53–60 x 9–11 µm, narrowly clavate, Bacidia-type. Ascospores 20–33 x (2–)2.5–2.7 (–3) µm, narrowly clavate-fusiform to shortly acicular, 3–5(–7)-septate.
Chemistry: thallus C--, KC--, K--, Pd--, UV--; no substances detected by TLC.
Lecania granulata has somewhat similar ascospores to L. subfuscula, which can also inhabit nutrient-enriched, coastal turf. L. granulata differs in having a thickly granular (blastidiate) thallus and a crenate to granular thalline margin. L. subfuscula has a generally thinner and warty granular thallus, with coherent ‘granules’ 40–200 µm diam, and usually darker pink to grey-brown or even blackish apothecia, with little hint of a thalline margin. L. cuprea is another species with narrow, multiseptate ascospores, but it has a thinner thallus, no thalline margin, smaller paraphysis apices, and inhabits shaded limestone rocks.
In GB&I, known from Scotland (Outer Hebrides (North Rona), Orkney and Shetland. So far endemic to Scotland.
Growing on coastal, peaty turf near cliff tops or on cliff ledges.