Polyblastidium hypocaesium (Yasuda ex Räsänen) Kalb
Mongkolsuk, Meesim, Poengsungnoen, Buaruang, Schumm & Kalb, Phytotaxa 235(1): 41 (2015)
Previously : Heterodermia hypocaesia (Yasuda) D.D.Awasthi
D. Awasthi, Geophytology 3: 113.1973; Singh & Sinha 1994: 419.
Basionym: Anaptychia hypocaesia Yasuda in Rasanen, J. Jap. Bot. 16: 139. 1940
Foliose, orbicular to irregularly spreading, loosely adnate, to 5 cm wide, but often coalescing to form colonies up to 15 cm wide
0.5–1.2 mm wide, to c. 2–3 (–5) mm wide at the tips, plane to weakly convex or weakly concave, sublinear-elongate, dichotomously branched, radiating; apices ascending, usually discrete, ± lobulate along the lobe margins, the lobules ± rounded or sparingly branched, 0.3–0.8 mm wide, 0.5–1.0 mm long.
Greenish white, whitish to cream-colored
Sorediate; soredia farinose to granular, in labriform to capitate soralia on lateral or terminal lobes, occasionally spreading along the lobe margins
Lower Side :
Ecorticate, ± compact, purple-black in the centre, white, ochraceous or yellow towards the apices. Marginal rhizines common, gray to black, simple or squarrosely branched, 1–3 (–5) mm long
Very rare, laminal, sub stipitate, 1–4 mm wide; margin lobulate, the lobules ecorticate, partly yellow on the lower surface, apically sorediate; disc concave, dark brown to blackish brown, sometimes very thinly gray-pruinose
Polyblastidia-type, ellipsoidal, with 2 or 3 small sporoblastidia, 35–45 × 16–20 μm. Pycnidia common, initially immersed, then becoming emergent, visible as black dots; conidia bacilliform, 4–5 × 1 μm
Cortex K+ yellow, C–, KC–, P+ yellow; medulla K+ yellow then red, C–, P+ yellow; pigmented medulla K– or K+ brownish green or K+ violet; containing atranorin (major), zeorin (major), japonene (major), salazinic acid (major), ± norstictic acid (minor), hybocarpone (minor), subhypocarpone (trace), 6α-acetoxy-22- hydroxyhopane-25-oic acid (trace), 7-chloroemodin (minor)