Observation 115016: Gymnopilus ventricosus (Earle) Hesler

When: 2012-10-27

Collection location: San Francisco, California, USA [Click for map]

Who: TaxoNerd (Taxo)

No specimen available

Analysis of these specimens. Suspected G. spectabilis/junonius, G. ventricosus, or related, large Gymnopilus.


rusty-brown, or amber-brown.

NOTE: In order to add to our collective body of scientific knowledge, I am interested in getting digital images of these spores, under magnification (200x-1000x). Please comment or contact me if you can help me to pursue this analysis.


cap 5-15cm diameter, some older specimens up to 35cm in diameter, convex becoming plane with age, incurved margin when young, yellow-orange-amber, taking on an overall amber or apricot hue after picking and handling and/or with age, drying to lighter yellow or orange, scaly, some with orange-brown spores on caps from nearby specimens, appears to bruise darker (to amber) from handling.


gills crowded or close, attached (adnexed or slightly notched), possibly seceding with age (no younger specimens available), bruising amber

NOTE: Published material states that G. spectabilis/junonius has attached to slightly decurrent gills. The gills on these specimens appear to be adnexed or slightly notched, however, I admit that this could be due to seceding. I will collect younger specimens in the future, from the same mycelial mat, to determine if seceding has caused the gills to appear adnexed. Regardless, please take a look at the close-ups, and comment. I am interested in knowing if this negates identification as G. spectabilis/junonius.


7-15cm long, 2-6cm thick, streaked with amber-brown fibrils, club shaped, not obviously ventricose, partial veil leaving annulus on stalk (on roughly half of specimens) and collecting rusty spores, off-centered growth from side of stump, stringy or fibrous inside (similar to spaghetti squash), solid. 


North Western portion of San Francisco, CA. 10/27/2012, roughly 1-2 weeks after first major Fall rains, temperatures over the past two weeks high 50’s to high 80’s (F). Growing in large, dense, and heavy clumps of up to 10 sporocarps, this cluster weighing 5-10lbs. on a stump (likely coniferous, as neighboring, landscaped trees were coniferous)


These specimens have a distinct “mushroom” odor that becomes stronger when the specimens are cut. A “nibble and spit” test left a strong, and less-than-desirable flavor in my mouth.

Note: I have not read a guide that mentions the amber staining that is present on the gills and stipe of these specimens, please comment with any insight into this aspect.


Veil-remnants on stipe and incurved-margin.
From Top to Bottom: Lamellae on Slide; veil remnants from margin, covered with spores, on paper; spore print on slide; spore print on paper. Notice lack of obvious gill pattern, due to abundant spore desposit.
Habitat: cluster in foreground has been removed from stump, another cluster can be seen in the background, still attached to the stump
Notice amber bruising on gills. Fibrils on stipe.
Note bruising on stipe.
Gills do not appear to be broadly attached to slightly decurrent, as the literature suggests, rather they appear adnexed to slightly notched.
The gills appear slightly notched on this specimen.
The inner stem is stringy and easily removed in strainds.
The cluster is dense, and the stipes become more broad toward, finally narrowing at the base.
Cross-section of the stipe.

Proposed Names

53% (1)
Recognized by sight
Used references: Audubon Guide to North American Mushrooms (Lincoff, 1981,1987), MushroomExpert.com, RogersMushrooms.com, mykoweb.com, Gymnopilus Key for PNW (http://www.svims.ca/council/Gymnop.htm).
72% (2)
Eye3 Eyes3
Recognized by sight: Large size, on conifer, western USA, not staining green

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Richard Kneal (bloodworm)
2012-10-31 09:46:47 PDT (-0700)

please email me @ bloodworm@shroomery.org
i would love to take a look at these.

Created: 2012-10-31 09:31:09 PDT (-0700)
Last modified: 2013-07-22 13:25:32 PDT (-0700)
Viewed: 109 times, last viewed: 2018-03-04 02:49:00 PST (-0800)
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