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

Pleurotus ostreatus (Fr.) P. Kumm.
oyster mushroom
Pleurotaceae

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

Introduction to the Macrofungi

© Alicia Yoshizawa  Email the photographer   (Photo ID #5963)

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Distribution of Pleurotus ostreatus
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Species Information

Summary:
The Pleurotus ostreatus complex is distinguished by smooth whitish to grayish to brownish caps with shelf-like habit, soft thick flesh, whitish gills, and whitish to lilac spore deposit. Vilgalys(4) have divided the complex in North America into Pleurotus ostreatus (Fr.) P. Kumm., Pleurotus pulmonarius (Fr.) Quel., and Pleurotus populinus O. Hilber & O.K. Miller, and this description is derived from theirs except where indicated. Other features of Pleurotus ostreatus in particular are relatively large, spathulate, scallop-shaped, or mussel-shaped caps, close to crowded gills, lilac to lilac-gray or light purplish vinaceous spore deposit, and spores 7.5-9.5 x 3.2-4 microns. Thorn(3) have shown that this species as well as other Pleurotus and Hohenbuehelia species attack and consume nematodes [roundworms]. The P. ostreatus complex is common in the Pacific Northwest, and includes lilac spored specimens over 15cm wide, at least in BC, but collections used by Vilgalys(4) from the Pacific Northwest are P. pulmonarius and P. populinus. Collections of this species used in the Vilgalys(4) analysis are from ON, AL, AR, AZ, CA, DC, FL, GA, IL, MD, MN, MS, NC, NJ, NY, PA, TN, VA, WI, WV, Czechoslovakia, France and Germany.
Cap:
(4)6-15(25)cm wide, convex, spathulate, scallop-shaped to mussel-shaped, margin inrolled becoming nearly flat when old and only slightly inrolled; whitish, yellow, pale yellow to grayish yellow, light tan to dark brown, also drab, light cinnamon drab, cinnamon drab, to light drab near margin, with some caps mostly pale cinnamon-pink; moist when young but never viscid, soon dry; finely white pubescent [downy] to pubescent over the lateral point of attachment to stem, smooth over the rest of the surface
Flesh:
up to 1cm or 2cm thick, firm, somewhat fibrous, solid; white
Gills:
adnate to mostly decurrent, close to crowded, broad, 0.5-1.5cm, with two tiers of subgills, sometimes forming a reticulum [network] near the point of attachment; dull whitish to pale pinkish buff; edge smooth at first, becoming eroded when old
Stem:
(0.5)1-3cm x 0.3-2(3)cm, laterally attached, stocky, nearly equal; dry, white pubescent to strigose at base
Odor:
pleasant and anise-like, becoming fungoid and unpleasant in age
Taste:
mild and pleasant in fresh specimens
Microscopic spores:
spores 7.5-9.5 x 3.2-4 microns, narrowly elliptic, [presumably smooth], inamyloid, colorless, thin-walled, with a small apiculus; basidia 4-spored, 24-36 x 5-7 microns, narrowly clavate, thin-walled, inamyloid, colorless; cheilocystidia and pleurocystidia infrequent to numerous, most often on gill edge, 14-30 x 3.5-8 microns, clavate-capitate, colorless, thin-walled; clamp connections present in all tissues
Spore deposit:
lilac to lilac-gray, to light purplish vinaceous

Habitat / Range

single, or more usually in large imbricate [shingled] clusters on the sides of stumps, logs and branches of hardwood trees, less commonly on conifers (Pinus - pine and Abies - true fir), fruiting during cool weather wherever hardwood hosts are found, especially fond of riparian habitat [fall, winter]

Taxonomic and Nomenclatural Links

Additional Range and Status Information Links

Edibility

delicious, douse in water to remove beetles between gills, remove stems, and check for white grubs (Arora for P. ostreatus complex)

Additional Photo Sources

Related Databases

Species References

Vilgalys(4) (P. ostreatus), Arora(1)* (P. ostreatus group), Phillips(1)* (P. ostreatus group), Lincoff(2)* (P. ostreatus group), Ammirati(1)* (P. ostreatus group), Miller(14)* (P. ostreatus group), Schalkwijk-Barendsen(1)* (P. ostreatus group), Kibby(1)*

References for the fungi

General References