Pertusaria

KEY 3: Key to isidiate Pertusaria in the western United States

1a. True isidia absent, thallus usually fertile; isidia-like papillae present; on mosses in arctic tundra...................................................... ........................................................................................................................................................................ P. bryontha (Ach.) Nyl.

1b. True isidia present, thallus often sterile; substrate various, distribution various ...............................................................................2

2a. All spot tests negative; distribution mostly eastern on moss and bark....................................................... P. globularis (Ach.) Tuck.

2b. At least one spot test positive; distribution various............................................................................................................................3

3a. Thallus K+ yellow to red, producing norstictic acid ..........................................................................................................................4

3b. Thallus K test otherwise, lacking norstictic acid................................................................................................................................5

4a. Isidia constricted at the base, subglobose to cylindrical, with enlarged, browned tips; usually on rock; containing connorstictic and subnorstictic acids as minor components ........................................................................................ P. pseudocorallina (Lilj.) Arnold

4b. Isidia not constricted at the base, globose to rarely cylindrical, with browned tips; usually on bark; lacking accessory metabolites ........................................................................................................................................................................ P. coccodes (Ach.) Nyl.

5a. Thallus P+ yellow to red-orange, C-, UV+ white, containing fumarprotocetraric acid; on soil or plant detritus................................ ................................................................................................................................................................. P. oculata (Dickson) Th. Fr.

5b. Thallus P- or P+ faint yellow, C+ orange, UV+ orange, containing thiophaninic acid; substrate various ........................................6

6a. Thallus K-, lacking atranorin, isidia apices often darkened and therefore K+ violet; distribution maritime on bark.......................... ...................................................................................................................................................... P. flavocorallina Coppins & Muhr

6b. Thallus K+ faint yellow, containing atranorin, isidia apices not darkened and therefore not K+ violet; distribution interior on mosses and rock...................................................................................................................... P. rayana J. Watts & E. Tripp , sp. nov.