Substrate: On the ground (one species on trees at low or high elevations)
Range: High elevations; (one species on trees at low or high elevations)
Description: A genus of mainly foliose, rarely fruticose lichens; upper cortex usually composed of a palisade-like pseudoparenchyma;
Colour: Yellow to yellowish green or brown
Pseudocyphellae: present or absent
Photobiont: green (Trebouxia).
Apothecia: Marginal or laminal but close to the margin, brown, with narrow asci
Spores: Colorless, spherical, 5 – 10 x 5 – 8 um, 8 per ascus arranged in a single row
Pycnidia: Prominent or immersed, distributed usually along the lobe margins on foliose species
Conidia: thread-like, 10 – 19 x 0.5 – 2 um.
Chemistry: Cortex PD-, K-, KC+ gold, C- (usnic acid); medulla of North American species with fatty acids.
Lookalikes: Most species of Allocetraria are found in southeastern Asia. The characteristics that link the two quite dissimilar North American representatives are mainly anatomical features (the cortex, pycnidia, & asci). Ahtiana is a closely related genus with dumbell-shaped conidia & a cortex of pseudoparenchyma (without a palisade arrangement.
Bibliography: Lichens of North America, by Brodo, Sharnoff, & Sharnoff
Database Entry: Distance Everheart 12-26-13