Diploicia canescens  

Thallus forming placodioid rosettes to 6 cm diam, often smaller and coalescing. Outer lobes radiating, thickly pruinose, closely contiguous, convex, pleated, 0.5-1 mm, wider at the margins, glaucous white. Lobe ends incurved, white-grey, verruculose and cracked-areolate towards the centre; soralia mainly laminal in irregular patches at first then coalescing; soredia green- white sometimes developing grey tips, finely granular.
Anamorph: pycnidial. Pycnidia more common on new lobes of fertile specimens, c. 0.04-0.50 mm diam., narrowly ‘U’-shaped in section, c. 0.24 mm tall, 60-70 µm wide; wall colourless; dark brown or green-black around the ostiole only. Conidia simple, rod-shaped 5-8 × 0.7 µm.
Teleomorph: ascomata apothecial. Apothecia 0.3-1 mm diam. locally common near the coast, rare inland; margin (true exciple) black with a marginal zone of crystals. Ascospores (8.5-)9-12(-15) × (4-)5.5-7(-7.5) µm.
Chemistry: Thallus C–, K+ yellow, KC+ yellow, Pd–, UV± dull orange (atranorin, chloroatranorin, diploicin and a xanthone).