Peltigera lepidophora
A small but distinctive Dogtooth with numerous flattened isidia on the partly thinly tomentose upper surface. A very rare species in Britian, only known form a single wooded gorge in eastern Perthshire.
Thallus to 5–7 cm diam., often smaller, level with or sunken into the substratum; lobes to 1 cm broad, ca 3.5 cm long, concave to ear-shaped, with ascending, entire or ± eroded and sometimes inrolled margins; upper surface grey-brown, smooth, glabrous in part or ± thinly tomentose to somewhat scabrous; isidia to 1 mm diam., numerous, button-like, resembling cephalodia, crowded and contiguous, sometimes overlapping or widely dispersed; lower surface with often rather indistinct white to pale grey, rarely pale brown anastomosing veins and discrete unbranched pale rhizines; photobiont Nostoc. Apothecia not known in Britain. Thallus with negative reactions; no lichen products detected by TLC.
Distinguished by the small size and numerous dorsiventral peltate cephalodium-like isidia on the partly thinly tomentose upper surface. Rather similar to the juvenile stage of Peltigera didactyla, which is sorediate and widespread.
On flat mossy rock ledges in a river gorge.
Very rare in a single ravine in E. Perthshire, Scotland.
Known only from a single location in a wood gorge on flat mossy rock ledges above the river. Potentially overlooked elsewhere but quite a distinctive Peltigera, so likely very rare. As a single population vulnerable to loss to random events.
Britain: Critically Endangered
Scotland: Priority Taxon for Biodiversity in Scotland
Cannon, P., Magain, N., Sérusiaux, E., Yahr, R., Coppins, B., Sanderson, N. & Simkin, J. (2021). Peltigerales: Peltigeraceae, including the genera Crocodia, Lobaria, Lobarina, Nephroma, Peltigera, Pseudocyphellaria, Ricasolia, Solorina and Sticta. Revisions of British and Irish Lichens 20: 1-34.
Text by Neil A Sanderson based on Cannon et al (2021)