Observation 82378: Agaricus californicus Peck

When: 2011-11-12

Collection location: Larkspur, California, USA [Click for map]

Who: Ron Pastorino (Ronpast)

Specimen available

These were growing on grass in a park.
The odor was unremarkable and neither the cap nor stem turned yellow with scratching.
The spores were ~ 5.0-6.1(6.8) X 4.0-5.0 microns.
With the tapering stem and habitat it does suggest Agaricus campestris. The spores may be a little smaller and those heavy scales confuse the issue.
Ran across the var. squammulosus on Mushroom Hobby, so might as well run it by and see if it sticks.
Well it didn’t stick because apparently it has been deprecated. However, it does still seem to be a valid name on Index Fungorum?



Proposed Names

-31% (2)
Used references: Mushroom Hobby website.
61% (2)
Eye3 Eyes3
Recognized by sight

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Add Comment
Membranous partial veil
By: Christian (Christian Schwarz)
2011-11-12 21:35:00 CST (-0600)

is a good indicator that it is not A. campestris, and an unremarkable odor is not unusual for A. californicus – I’d say that’s what you’ve got. The spores are well within range.

Also, although the base is tapered, it has a constriction and then a knob that I see more in section Xanthodermati. A. campestris sensu CA pretty much just evenly tapers.

(I see some yellow on the base in photo #2)

I wouldn’t rule out a weird
By: Noah Siegel (Noah)
2011-11-12 19:41:56 CST (-0600)
The cap of the largest specimen
By: Ron Pastorino (Ronpast)
2011-11-12 19:36:09 CST (-0600)

was about 7.8 cm across and it’s stem ~ 6 X 2 cm.
There wasn’t any staining of the context that I could see.
Haven’t looked for any cystidia.
KOH on the cap surface turned a very light yellow after a few minutes.

KOH rxn?
By: Noah Siegel (Noah)
2011-11-12 19:22:22 CST (-0600)
More info?
By: Byrain
2011-11-12 18:52:18 CST (-0600)

How big are they? Cap diameter & stem length? Does the context stain? Did you look for cheilocystidia?

Created: 2011-11-12 18:38:10 CST (-0600)
Last modified: 2011-11-12 23:15:04 CST (-0600)
Viewed: 92 times, last viewed: 2018-07-16 12:16:01 CDT (-0500)
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