Allocetraria oakesiana (aka Cetraria oakesiana & “Yellow Ribbon Lichen”)

Location Summary

Substrate: On bark & wood, usually of conifers or birch; sometimes on rock; typically in shaded forests.

Range: All throughout North America, except Nevada, northwest Alaska, & northeast Canada.

Identification Characteristics

Description: mostly appressed; lobes strap-shaped, crisped at the edges, branched, 1 – 4 mm wide. Lower surface pale brown to almost white, somewhat wrinkled, shiny, with sparse rhizines.

Color: Yellowish green, uniform.

Pseudocyphellae: None

Sorelia: Yellowish, almost entirely marginal, granular, sometimes developing from coarse pustules

Lobules: Rarely with tiny, almost granular lobules.

Medulla: White to pale orange.

Photobiont: Green (Trebouxia).

Apothecia: Rare, marginal or laminal, with pale brown disks.

Spores: Spherical, ca. 5 um in diameter

Conidia: Usually thread-shaped, 8 – 10 um long, but rather variable in shape & size.

Chemistry: Medulla PD-, K+ yellow, KC+ orange to red-orange, C- (caperatic, protolichesterinic, lichesterinic, & secalonic acids).

Lookalikes: Except for the color, this species is similar to Tuckermannopsis chlorophylla.  It is also very close to species of Ahtiana but has different conidia.

Bibliography: Lichens of North America, by Brodo, Sharnoff, & Sharnoff

Database Entry:  Distance Everheart 12-26-13