Observation 224308: Candelariella aurella (Hoffm.) Zahlbr.

When: 2015-09-16

Collection location: Cholame Valley, California, USA [Click for map]

Who: J-Dar

Specimen available

On old concrete foundation in arid grassland setting.

Thallus scarcely visible, apothecia yellow with raised thalline margin. Thallus and apothecia K-, C-. Hypothecium hyaline to light brownish. Asci clavate. I couldn’t tell if there were 8 or more ascospores, just couldn’t get a clear shot under the microscope. Paraphyses simple, often swollen or club-shaped at tip, but didn’t get measurement. Mature spore measurements, in micrometers:

In order to get C. aurella, I had to go with 8 spores per ascus. Spore measurements are consistent in length, but slightly larger in width, for this species.


Hyaline spores, single-celled, narrowly ellipsoid

Proposed Names

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Used references: Nash Sonoran Flora

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Add Comment
I’ve been told “Wilkinson Sword” are the best
By: Jason Hollinger (jason)
2015-12-04 14:35:01 CST (-0500)

If hard to find, I can send a few packets. Fresh blade definitely helps. Some moss crusts and parasites even a fresh blade won’t work, then can drop some apothecia whole into a fleck of elmer’s glue on a slide, dries super quick, then easier to hold still to get a good section.

But on concrete, without obvious thallus, almost certainly aurella. Very common all over on concrete. … But if concrete is in an area with abundant C. rosulans, watch out for that, I’m sure I’ve seen rosulans spill over onto concrete, but only if concrete is a tiny island amid massive granite/rhyolite/siliceous community.

I added KOH to the mount
By: J-Dar
2015-12-04 14:20:46 CST (-0500)

which helped, but I still just couldn’t get a clear image of the ascospores. I definitely struggled with getting a thin enough slice because the apothecia were so small and they dislodged from the substrate easily. Is there a surgical razor blade that is thinner or works better than a standard one?

To get better count of spores…
By: Jason Hollinger (jason)
2015-12-04 12:47:44 CST (-0500)

You can try mounting in KOH instead, then gently squashing. Thinner sections will be clearer, too, but more asci will be damaged.

Created: 2015-12-02 22:20:38 CST (-0500)
Last modified: 2015-12-04 12:46:08 CST (-0500)
Viewed: 49 times, last viewed: 2018-01-09 16:09:35 CST (-0500)
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