Location: 50°36’21.49"N, 114°58’49.52"W, el. 2430m. Ptarmigan Cirque is 2 km E of Highwood Pass.

Photos of Rhizocarpon geographicum and Rhizocarpon macrosporum from Pocaterra Cirque Trail, Highwood Pass, Kananaskis Country, Alberta
  Rhizocarpon   Rhizocarpon   Rhizocarpon

Species Lists


Proposed Names

28% (1)
Recognized by sight
56% (1)
Recognized by sight: I think this is the best name for unidentified yellow Rhizocarpon in absence of data on spores or chemistry.

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= Observer’s choice
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Rhizocarpon characters
By: Chris Parrish (kitparrish)
2012-01-16 14:55:06 PST (-0800)

Brodo and Bruce Ryan both address Rhizocarpon on a continental scale, and both use a two-way classification to begin their analyses:

A1. Thallus yellow
A2. Thallus brown, gray, or whitish

Then under each of those subdivisons:

B1. Spores 3-septate to muriform
B2. Spores one-septate

After that the discussions get very technical very quickly, involving details of areole geometry and dispersion, chemistry (C, K, IKI), fine structure of the apothecium (hymenium, epihymenium, relationship to surrounding areoles), and spores (sizes, colors, and number per ascus).

Bruce Ryan, in particular, remarks that Rhizocarpon is a very difficult genus.

By: Byrain
2012-01-16 11:37:23 PST (-0800)

What kind of chemistry is most helpful for this group?