Thallus to 4(-6) cm tall, pale green, erect to subpendulous (then 4-10 cm in length) or scrambling (up to 25 cm), forming loose, rather irregular tufts, richly branched especially towards the ends. Main branches rather stout, inflexible, to 1 mm diam., lateral branches finer, not constricted at the base. Thallus surface pale green- to yellow-grey, not blackened at the base but sometimes with red-brown pigmentation, smooth and shining, at times with inconspicuous annulations. Soralia minute, punctiform, even and flat, numerous, mainly on terminal branches. Isidia also developing on young branches but rapidly becoming abraded. Cortex thin, 8-15% of diam., medulla compact.
Anamorph: not known.
Teleomorph: not known.
Chemistry: medulla C–, K–, KC–, Pd+ red (usnic and protocetraric acids).
Assessed as Vulnerable (D2) and Nationally Rare by Woods & Coppins (2012); locally frequent but very restricted in distribution.
A rather coarse, scrambling species, with conspicuous main branches with a tendency to form loose, disorganized tufts. It has a dense, compact medulla, a relatively smooth, hard cortex ± mottled with minute, punctiform soralia, bearing short fragile isidiomorphs which are often poorly developed; extensive areas of the cortex may remain smooth and ± shining except for the soralia.
U. glabrata, is erect and shrubby, contains fumarprotocetraric acid (Pd+ red), has a lax medulla, a smooth, shining cortex and large soralia. The habit of U. subscabrosa recalls that of U. flammea which has a semi-lax medulla and contains stictic acid.
In GB&I, restricted to extreme SW England (reported from the Lizard peninsula and Isles of Scilly). The Lizard report may well be erroneous, and the species should be searched for in suitable maritime habitats in the Land's End area.
Amongst low vegetation (often in Calluna heath) and on rocks.