Observation 178791: Collema nigrescens (Huds.) DC.
When: 2013-06-26
(35.6484° -83.0562° 1185m)

Notes: on mossy bark of leaning dead Carya

open old hardwood forest on ridge

no isidia, abundant apothecia, olive-brown thick stretched thallus, photobiont obvious strings of Nostoc, exciple of radiating branching sparse fibrous hyphae, spores 8 per ascus hyaline ellipsoid-fusiform 1-septate ~15×5um

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Good catch, zaca
By: Jason Hollinger (jason)
2014-10-07 15:32:47 PDT (-0700)

Either I only saw immature spores… or this is a new report for the Smokies! :) Here’s the list of foliose nonisidiate nonpruinose corticolous Collema from the Smokies checklist:

C. ryssoleum – spores 4-6-septate, 26-40µm long
C. leptaleum – spores 4-septate, 25-50µm long
C. nigrescens – spores mult-septate, > 50µm long

I know C. nigrescens is supposed to have a fibrous medulla (as shown here), and it is supposed to be a widespread and common species throughout eastern North America (along with the sometimes apparently very similar C. pulcellum). I don’t know much about the other two. Some sources claim C. ryssoleum is saxicolous (B. Ryan’s unpublished keys). And C. leptaleum seems to mostly be a southern thing (so therefore presumably uncommon in the Smokies, one presumes).

Let’s just assume the spores I saw were immature and stay with C. nigrescens! :)

Is there any …
By: zaca
2014-10-07 15:05:32 PDT (-0700)

misprint in the dimensions of the spores. If not with that features I only know C. conglomeratum, but there may exist other species in N.A.

Created: 2014-09-15 23:10:40 PDT (-0700)
Last modified: 2014-09-15 23:10:45 PDT (-0700)
Viewed: 37 times, last viewed: 2016-10-06 03:19:20 PDT (-0700)
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