Pleurotus ostreatus

Pleurotus ostreatus
Image Courtesy of Peter Katsaros
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Group of Fungi: Agarics

Family: Pleurotaceae

Latin Name: Pleurotus ostreatus (Jacq.) P. Kumm.

Common Name: Oyster Mushroom

Description: Fan-shaped, semicircular or oyster shell-shaped (hence the common name) structure; cap 2–8 in (5–20 cm) or across and 1/8–1/4 in (0.3–1.0 cm) thick, upper surface white to dull grayish brown, smooth; margin often shallowly lobed or wavy; gills moderately well separated, radiating from the point of attachment of the cap, white at first but becoming pale yellow in age; stalk often absent but when present off-center and rudimentary; spores white to buff to pale lilac-gray in mass.

Biological Role: Decomposer of wood.

Habitat: On fallen logs and stumps of broadleaf trees or very rarely conifers; usually occurring in overlapping clusters.

Geographical Distribution: Widely distributed throughout North America but more common in the east.

Comments: The fungus recognized in most field guides as Pleurotus ostreatus is a species complex consisting of a number of forms that are morphologically almost identical. All are considered choice edibles. However, when collecting specimens for human consumption, it is important to distinguish one of these from similar fungi (for example, species of Crepidotus) that are not edible.

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