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Arctocetraria nigricascens (Nyl.) Karnefelt & Thell (redirected from: Cetraria nigricascens)
Family: Parmeliaceae
[Cetraria elenkinii Krog,  more]
Arctocetraria nigricascens image
Lucy Taylor  
Thompson, J., 1984. American Arctic Lichens: The Macrolichens.
Thallus dorsiventral but loose on the substratum and rising almost fruticose, lobes to 2 mm broad and to 4 cm long, slightly channeled above; upper side dark olive-brown to blackish brown, smooth; underside nearly the same color, slightly dented in spots; pseudocyphellae few or absent; margins with cilia which are simple or sparingly branched; tips not rounded, pointed; pycnidia nearly lacking. Cortex prosoplectenchymatous. Apothecia not known.

Reactions: K -, C —, KC -, P -.

Contents: rangiformic and norrangiformic acids.

Growing on soils and the twigs of Betula this species appears to be a rather rare member of the Beringian element in the arctic, ranging in the rare collections as far east as Baffin Island in the American Arctic.