Observation 65536: Inocybe sensu lato (Site ID) (Inocybaceae)

under blue oak.
collected by David Rust.

Species Lists


pileipelis a trichohymeniderm.
note curious elongated golden cells in pileus context.
cap with low umbo.
broken stipes, incompletely collected.
context pale orange, color unchanging with exposure.

Proposed Names

57% (1)
Recognized by sight: silky fibrillose cap with low umbo (NOT peaked or conic), pruinose, long rooting stipe (incompletely collected).
Based on microscopic features: from spore drop: spores elliptical to bean shaped, smooth with speckled contents(some still moving around!), thick-walled, 12-13 × 5-6 microns; pileipelis a trichohymeniderm.
Based on chemical features: fruity, slightly unpleasant odor. KOH negative on cap.

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= Observer’s choice
= Current consensus


Add Comment
By: Paul Sadowski (pabloski)
2011-06-07 22:57:36 CDT (-0500)

Could that tortuous long cell be a lactifer? It’s been useful to study the micrographs here. Thanks for them and the comments.

By: Martin Livezey (MLivezey)
2011-06-07 14:55:49 CDT (-0500)
a rare and unique Inocybe, according to Brandon Matheny…
By: Debbie Viess (amanitarita)
2011-06-07 14:44:16 CDT (-0500)

Hi Debbie,
I haven’t scoped the collection yet but we have obtained the ITS and this sequence is unlike anything we have sequenced to date and unlike anything sequenced from Europe to date. It is probably closely related to Inocybe bulbosissima, a European species evidently associated with Salix and about which I know next to nothing, based on ITS similarities. The most closely related sequences (95% similar) are from samples of Kobresia (Cyperaceae) ectomycorrhizal roots taken from alpine meadows in the eastern Himalaya of China.

Your Blue Oak associate is part of the greater Inocybe rimosa complex but at present most likely lacks a name. A comparison with the Japanese literature is probably in order, but I have not done that yet. Brad Kropp, from Utah State, and I are in the works of documenting 8 species of the I. rimosa complex from Utah and Washington (five of which will be described as new, mostly from high elevation conifer stands or with Mountain Mahogany) and yours matches none of them.

Good find!


By: Debbie Viess (amanitarita)
2011-05-02 11:35:19 CDT (-0500)

Brandon wrote that it will be DNA analyzed soon.

So this seems to be Mallocybe
By: Gerhard Koller (Gerhard)
2011-04-17 17:57:00 CDT (-0500)

or maculata-group?

By: Debbie Viess (amanitarita)
2011-04-17 11:39:05 CDT (-0500)

collection in part sent to Brandon Matheny for DNA analysis.