[1] It was first described from Yemen and is characterised by its blackish thallus, abundant small apothecia (fruiting bodies), and cyanobacteria from the genus Nostoc as its photobiont.

The type specimen of Lempholemma polycarpum was collected in Shah-ot, Damkaur, Al Mahrah Governorate, Yemen, on small inclined limestone boulders at an elevation of 680 m (2,230 ft).

[2] Microscopically, the mycobiont forms a loose network of elongated hyphae that becomes denser towards the lobe margins, with cells measuring 10–17.5 by 1.5–2 (up to 5) μm.

Lempholemma radiatum has elongated, radiating lobes that are longitudinally ridged and plicate, and it differs in the presence of isidia, the type of ascoma ontogeny, and a more or less arctic distribution.

[2] Lempholemma polycarpum grows on inclined limestone boulders in sun-exposed habitats on rocky slopes with open forest vegetation.