E-Flora BC: Electronic Atlas of the Flora of British Columbia

Gymnopilus ventricosus (Earle) Hesler
jumbo gym

Species account author: Ian Gibson.
Extracted from Matchmaker: Mushrooms of the Pacific Northwest.

Introduction to the Macrofungi

© May Kald  Email the photographer   (Photo ID #20161)

E-Flora BC Static Map
Distribution of Gymnopilus ventricosus
Click here to view the full interactive map and legend
Details about map content are available here
Click on the map dots to view record details.

Species Information

Arora refers to this as the large non-hallucinogenic conifer-loving western member of Gymnopilus spectabilis group with a swollen stem and membranous veil, (if in fact truly distinct from G. spectabilis), that can reach more than 40cm in diameter, noting that young specimens "present an entirely different appearance: squat and compact with hard, very thick, yellow flesh and very narrow (shallow gills)"; Hesler(2) (describing one collection from CA) gives cap as 7-8cm and gives distinctive features as reddish brown cap with minute yellow fibrils, heavy ventricose stem, subsinuate gills, slightly dextrinoid spores and interwoven cap tissue; found at least in CA, and according to Phillips in the Pacific Northwest; many collections identified as G. spectabilis are in fact G. ventricosus (Stamets); Trudell(4) comment in 2009 about the Pacific Northwest, with Latin names italicized, "Two such species occur in our region. The more common one is Gymnopilus ventricosus ... The less common species in our region, G. junonius (=G. spectabilis), occurs on both conifer and hardwood substrates and typically is somewhat smaller with a thinner stipe."; collections from BC labeled as G. ventricosus deposited at University of British Columbia, recorded from Cape Lookout on the OR Coast, in Olympia, WA and in northern ID (by M. Beug, pers. comm.)
7-8cm across, convex, obtuse; reddish brown, often with a lighter disc; subdry [more or less dry], minutely yellow-fibrillose or almost bald, margin subappendiculate from hanging fibrous veil remnants, (Hesler), up to 40cm or more across, (Arora)
pale yellow, unchanging, (Hesler)
subsinuate, crowded, rather broad and subventricose [somewhat broader in middle]; pale brown becoming dark cinnamon; edges thin and entire, (Hesler)
14-18cm x 2-3cm, solid, conspicuously ventricose [wider in middle]; pale brownish; with white fibrils in upper part and with fine yellow fibrils (or more or less bald) lower down, rooting and covered with a white mycelium at the base, (Hesler), swollen stem with membranous veil (Arora)
forms a thick persistent almost apical ring with margin jagged and remaining erect, (Hesler)
none (Hesler)
bitter (Hesler)
Microscopic spores:
spores 7.5-9 x 4-5.5 microns, elliptic, oval or subamygdaliform [somewhat almond-shaped] in face view, inequilateral in side view, verruculose [finely warty], no germ pore, slowly dextrinoid; basidia 4-spored, 23-27 x 6-8 microns; pleurocystidia 27-31 x 6-7 microns, "fusoid-ventricose or flask-shaped, often with a brown pigment", cheilocystidia 26-33 x 5-8 microns, "flask-shaped with a neck, more or less capitate"; gill trama subparallel to parallel, hyphae 5-7 microns wide; cap trama interwoven, cuticle "of more or less repent hyphae bearing tufts of pallid to brownish hyphae"; clamp connections present, (Hesler)
Spore deposit:
rusty brown (Phillips)

Habitat / Range

type in a dense colony at the base of living pine, gregarious or cespitose [in tufts] (Hesler)

Taxonomic and Nomenclatural Links

Additional Range and Status Information Links


no (Phillips), but not hallucinogenic (Stamets)

Additional Photo Sources

Related Databases

Species References

Hesler(2), Phillips(1)*, Stamets(1)*, Trudell(4)*, Arora(1), AroraPocket*

References for the fungi

General References