Observation 169576: Agrocybe pediades group

When: 2014-07-07

Collection location: Medford, Jackson Co., Oregon, USA [Click for map]

Who: Ron Pastorino (Ronpast)

Specimen available

Growing on a lawn.
Spores ~ 13.9-17.0 X 9.9-13.2 microns, broadly ellipsoid to ellipsoid with large germ pore.
Looking at the photos a little more closely, they do appear more Agrocybe-like….some veil remnants on edges of cap and the stem is not real fragile or smooth. Spores are not rough enough for P. foenisecii. However, with the very large spores, it would appear to be closer to A. platysperma.


Spores in KOH @ 1000X.
Spores in KOH @ 1000X.
Gill cystidia @ 1000X.
Gill cystidia @ 1000X.

Proposed Names

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Recognized by sight
28% (1)
Recognized by sight
Based on microscopic features

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Add Comment
By: Byrain
2014-07-13 17:42:24 CEST (+0200)

A. pediades should of variable spore sizes, also you really should check for pleurocystidia as A. ochracea seems to occur in the west, but maybe not on a lawn… I’m doubtful there is enough info in the A. platysperma description to distinguish it form A. pediades, maybe its the same thing even?

There is some information
By: Ron Pastorino (Ronpast)
2014-07-13 00:36:13 CEST (+0200)

re A. platysperma in the comments of this observation…
All the references I am finding show smaller spores for A. pediates, especially the width, usually below 8 microns.
I made a quick attempt to find gill cystidia and only found a smattering that seemed to be cheilocystidia and rather small, ~ 35 X 7-8 microns, lageniform with a sl. pinched neck.
Two other Agrocybe species are mentioned in the Pacific Northwest Keys….A. semiorbiculars and A. steposa, purportedly similar but having larger spores.

More info please!
By: Byrain
2014-07-12 19:37:51 CEST (+0200)

Pleurocystidia present or absent? Cheilocystidia? What is your reference for A. platysperma? Your spores are in range for A. pediades.

“Spores (10.5)11.5–18.5(20.0) × 7.5–12.0(15.0) × 7.0–10.5(12.5) μm,
on average (12.0)12.5–16.0(17.0) × 8.0–11.0(13.0) × 8.0–9.5(10.5) μm”

You should save these.

Created: 2014-07-12 18:22:01 CEST (+0200)
Last modified: 2014-07-13 17:42:46 CEST (+0200)
Viewed: 103 times, last viewed: 2017-07-10 16:41:43 CEST (+0200)
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