Anamorph: conidiomata pycnidia, 100–130 μm, globose. Conidia 3–4(–5) × 0.5–1 μm, bacilliform, aseptate, hyaline.
Teleomorph: ascomata perithecia, immersed in the hymenia of the host, (130–) 180–220 μm diam. and 230-300 µm tall, pyriform with a broad neck that hardly extends beyond the surface of the hymenium. Peridium hyaline to pale brown below, strongly aeruginose or ± brownish blue around the ostiole, 10–15 μm thick toward its base, composed of thin-walled isodiametric cells. Interascal tissue of abundant cellular pseudoparaphyses 1–1.5 μm diam, only scarcely branched and anastomosed. Asci 50–70 × 9–13 μm, cylindric-clavate, the base tapering and the apex rounded, thick-walled and fissitunicate, mostly 4- or 8-spored. Ascospores (15-) 17.5-20.5 x 5-5.5 µm, ovoid to ovoid-fusiform, hardly constricted at the ± median septum, hyaline, smooth, without an epispore or gelatinous sheath.
Assessed by Woods & Coppins (2012) as of Least Concern, but listed as Nationally Scarce. It is likely to be overlooked.
Material on Lecanora stenotropa has been referred to by Calatayud et al. (2013) as L. stenotropae ad int. based primarily on 4- rather than 8-spored asci, but collections on L. polytropa may also show this feature.
On apothecia of Lecanora polytropa and rarely L. intricata.
Throughout the British Isles, though not recorded from SW England.