Psora tuckermanii

Psora tuckermanii Timdal

Languages: English



Squamules: up to 6 mm wide, elongate, imbricate, weakly concave to weakly convex; upper surface: light brown or medium brown, dull, epruinose or partly pruinose, smooth or sparingly fissured; margin: concolorous with upper side or white, down-turned or straight, entire or lobed; upper cortex: up to 60-120 μm thick, composed of thin-walled hyphae with round lumina, not containing crystals of lichen substances, sometimes containing calcium oxalate; medulla: not lichen substances, often containing calcium oxalate; lower cortex: of mainly periclinally oriented hyphae, not containing calcium oxalate; lower surface: white to medium brown; Apothecia: up to 1.5 mm diam., laminal, convex and immarginate even when young, medium brown, epruinose or white or yellow pruinose; ascospores: 8-12 x 6-8 μm; Pycnidia: unknown; Spot tests: upper cortex and medulla K-, C-, KC-, P-; Secondary metabolites: none.


Diagnostic Description

Psora tuckermanii shows an extensive morphological variation, and may be confused mainly with P. himalayana, P. luridella, P. pseudorussellii, and P. russellii; see these species for discussions.

Look Alikes

Psora himalayana, Psora luridella, Psora pseudorussellii, Psora russellii.

Ecology and Distribution


Western North America.


On soil and rock in open habitats, mainly in pinyon-juniper woodland, conifer forests, and Great Basin desert scrub.


Schneider, G. (1979).  Die Flechtengattung Psora sensu Zahlbruckner. 291. Abstract
Timdal, E. (1986).  A revision of Psora (Lecideaceae) in North America. The Bryologist. 89, 253-275. Abstract
Timdal, E. (2002).  Psora. (Nash I., Ryan B., GriesC., BungartzF., Ed.).Lichen Flora of the Greater Sonoran Desert Region. I, 418-430. Abstract