Physconia muscigena

Common name	Ground Frost Lichen
Code	PHYSMUS
Field Characters	Small, narrow-lobed, foliose chlorolichens. Thalli typically attached throughout or slightly ascending at the lobe tips, typically forming extensive colonies. Lobes typically < 2 mm across, branching regularly, equal in width throughout. Upper cortex grey to brown, often extensively pruinose (giving the genus the common name of Frost Lichens). Medulla white. Soredia and isidia absent, occasionally form ing marginal lobules. Lower cortex typically black, in some specimens pale distally and only darkening towards the centre. Rhizines typically abundant, black, squarrosely branched and often visible as a fringe of pipecleaner-like structures around the lobe edge. Apothecia occasional.
Similar species & genera	Phaeophyscia constipata: generally lacking regular pruina, ciliate, with a pale lower cortex. Because the two species grow intertwined they can sometimes be hard to separate, particularly when hydrated.
Ecology	Terricolous, rarely saxicolous in open grassland and alpine habitats.
Chemistry	All spot tests negative (no substances detected).
Molecular support	In progress, as part of work by Esslinger and Leavitt to better delineate Physciaceae in North America.
Links	ABMI Biodiversity Browser Consortium of Lichen Herbaria Ways of Enlichenment Photo Gallery
Gallery