Observation 214030: Arthonia elegans (Ach.) Almq.
When: 2015-08-18
Who: zaca
No herbarium specimen

Notes: Growing on bark.

Proposed Names

29% (1)
Recognized by sight
58% (1)
Eye3 Eyes3
Used references: British Flora
Based on microscopic features
Based on chemical features: K+ purple on thallus

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Eye3 = Observer’s choice
Eyes3 = Current consensus

Comments

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Microscopy added.
By: zaca
2015-08-30 05:34:00 PDT (-0700)

The microscopy was bad but I could not repeated it.
However, in this case, that is enough to achieve the species. Though a small number was observed, the spores are hialine when young and brown at maturity, few septate (3-4 septa) with the upper cell enlarged, with sizes 17-18 × 7-7.5 um. This together with the K+ purple reaction on thallus clearly points to Arthonia elegans, since, according to the British Flora, only two species of Arthonia have a purple pigment soluble in K: A. cinnabarina and A. elegans. The former, wich is most common here, has larger and more septate spores.

Created: 2015-08-25 11:10:31 PDT (-0700)
Last modified: 2015-08-30 05:33:18 PDT (-0700)
Viewed: 22 times, last viewed: 2016-10-28 15:21:19 PDT (-0700)
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