Observation 21470: Umbilicaria muehlenbergii (Ach.) Tuck.
When: 2009-05-14
No herbarium specimen

Notes: Identification: U. phaea and U. muehlenbergii have largely complementary ranges, according to the range maps in Brodo (2001). U. phaea is found in western North America and U. muehlenbergii is found in northern and northeastern North America. U. muehlenbergii is “common throughout the [New England] region” (Hinds and Hinds, 2007, p.483). Brodo’s key separates these two species by characteristics of their undersurfaces, which is hardly visible in this photo, but their apothecia differ. The apothecia of U. phaea have concentric ridges (gyrose), while the apothecia of U. muehlenbergii consist of “radiating, branched ridges split by fissures” (Brodo, 2001, p.704). At this point I will leave it to the interested reader to approach this photo on his computer screen with his 10x lens …

Additional images added on 01 June 2009. It’s still a stretch to try to bring those apothecia into focus. I’m with Jason on this one: “radiating, branched ridges split by fissures” sounds like perfect material for microscope pictures!

Proposed Names

28% (1)
Eye3
Recognized by sight
Used references
-28% (1)
Recognized by sight: inset angular gyrose black apothecia (and shiny medium brown surface confirms)
61% (2)
Eye3 Eyes3
Used references: Brodo, et al., 2001, pp.686-709; Hinds and Hinds, 2007, pp.477-487

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Eye3 = Observer’s choice
Eyes3 = Current consensus

Comments

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I stand corrected
By: Jason Hollinger (jason)
2009-06-01 10:21:08 PDT (-0700)

Too bad I didn’t bother to look at the range in Brodo’s book! :) Too bad, also, that you don’t have a closer photo of the apothecia — I’d love to see the difference between “radial fissures” and “angular gyrose”…

Created: 2009-05-31 08:06:36 PDT (-0700)
Last modified: 2010-08-13 20:15:56 PDT (-0700)
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