Observation 275315: Agaricus L.

Found under Juniperus occidentalis in sandy soil as mush humps. Although they were covered with soil the caps were completely open.


Copyright © 2017 Debbie Viess
Agaricus showing volva. Gills a narrow layer on thick cap context.
Copyright © 2017 Debbie Viess
Agaricus at least 1 week after collecting. No staining after cutting or KOH.
Copyright © 2017 Debbie Viess
spores from spore drop, in water, 400x
Copyright © 2017 Debbie Viess
Spores from spore drop, in water, 1000×. 5.5 × 5.5, 5.5 × 5, 5.25 × 4.5, 5 × 5.5.
Copyright © 2017 Debbie Viess
spores from smash mount after drying; much more elliptical in shape. 400x, in water.

Proposed Names

82% (1)
Recognized by sight
55% (1)
Recognized by sight: Habitat, stature, smooth white dirty cap, sheathing at base, No red staining noted.
Based on microscopic features: Spores within range
Based on chemical features: KOH neg

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= Observer’s choice
= Current consensus


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Bob passed off the specimens to me in Portland.
By: Debbie Viess (amanitarita)
2017-05-03 16:25:46 CDT (-0500)

A few more details:

KOH negative. No staining when cut after ten minutes.
Odor, after several days, worked itself up to mildly “mushroomy,” like a bisporus.
Little to no odor when first examined.

Cap with a smooth “kidskin” texture, with an over-hanging cap margin.
sl. bulbous base, smooth along mid-lower stipe, more textured towards apex.

Spores were globose to semiglobose from spore print, much more elliptical in gill smash mount from dried material. But as Kerrigan states, once you refrigerate Agaricus, all spore bets are off! They change both shape and size. Yee gads!

Scant cheilocystidia present; spores w/prominent apiculus, thick walled, 5.5 × 5.5, 5.5 × 5, 5.25 × 4.5, 5 × 5.5. I did not measure the smash mount spores.

Of particular interest to me was the fact of this Agaricus having a volva or perronate PV.

I took it thru the keys in Kerrigan’s book, but came up with nothing that matched.

I will send Bob my micrographs to post here.

Yes, I still have this in my herbarium. It’s Rick’s for the asking! So please change this obsie, Bob, to reflect that specimens do exist.

Can’t wait to hunt with you and Rick in AZ in August!

Created: 2017-05-01 15:19:01 CDT (-0500)
Last modified: 2017-05-05 17:42:35 CDT (-0500)
Viewed: 57 times, last viewed: 2019-05-28 05:04:58 CDT (-0500)
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