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|I’d Call It That||3.0||6.06||1||(Andrew)|
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I’m now noticing the difference in the presence/absence of those black apotheicia. that looks like one of the best up-front distinguishing characteristics.
what’s an ink mount?? I’d google it, but your answers are like a siren’s call to lichen island. :)
Rhizocarpon consists of alternating tiles of black (apothecia) and yellow (thallus), with a distinctive thin black background (prothallus). Acarospora and Pleopsidium both are made up entirely of yellow areoles (thallus) with the apothecia (typically mild-colored) immersed inside these areoles. Microscopically they are completely different, Acarospora and Pleopsidium have numerous tiny hyaline simple spores stuffing each ascus, while Rhizocarpon has larger spores either hyaline or brown, and either septate to full-on muriform. Rhizocarpon spores also have a thick soft gelatinous perispore which shows up on an ink mount as a clear, diffuse halo. (R. Droker posted an excellent photo of this phenomenon.)
…P. chlorophanum differs from P. flavum in having a smooth, smaller squamulose thallus, and larger apothecia… P. chlorophanum is a rare, alpine species in Europe… P. flavum is a Mediterranean species… with a broader ecological amplitude. It is assumed P. chlorophanum occurs in North America at high elevations, but so far we have seen only one specimen from North America [from Channel Islands in southern California]."
Created: 2012-11-12 13:04:18 CST (-0500)
Last modified: 2012-11-12 13:07:58 CST (-0500)
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