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EDIBLE AND POISONOUS MUSHROOMS OF CANADA
PLEUROTUS PORRIGENS (Fr.) Kummer
Figure 156,'page 91
piLEUS sessile, laterally attached, elongated, ^/2-3 in. long, up to 2 in.
broad, at first resupinate with inrolled margin, expanding to almost plane, or
depressed toward the base, narrowing toward the base, variable in shape,
mostly fan-shaped to ear-shaped, white, watery and sUghtly striate on the
margin when moist, varying from almost glabrous at the margin to densely
tomentose at the base, sometimes lobed on the margin, flesh thin, white,
fragile, odor and taste mild, lamellae mostly reaching the point of attach-
ment, close, rather narrow, Hnear, white or cream, in some specimens showing
a certain amount of forking near the base, stipe lacking, base somewhat white-
mycelioid. spores smooth, white, subglobose to broadly ovoid, 5-7.5 X 5-6 /z.
In overlapping, shelving clusters, on decaying wood of conifers. Sept.-
Nov.
A number of whitish species of Pleurotus that may key out here are
known. From our herbarium records, P. porrigens appears to be the most common,
but the others are often difficult to distinguish and some can be determined
only by microscopic characters.
The fruiting bodies of one group of species, including P. porrigens, are
resupinate when very young but soon become reflexed, whereas those of
another group are never resupinate. Among the resupinate forms, P. albo-
lanatus Pk. in Kauffm. differs in having a gelatinous layer of tissue in the
pileus, and is more hairy. P. porrigens appear slightly hairy when dry, especially
toward the base, but P. albolanatus is decidedly hairy alL over and is a larger,
firmer plant. Among the nonresupinate forms, P. petaloides Fr. is a brownish'
mushroom with sHghtly smaller spores and also has cystidia on the lamellae.
P. porrigens lacks cystidia. P. spathulatus (Fr.) Peck has ovoid-eUipsoid spores.
Panus angustatus Berk, is another species that might be confused with this
group. It is tougher in consistency, has cystidia on the lamellae, and has a
gelatinous layer of tissue in the pileus.
PLEUROTUS SAPIDUS Kalchbr.
Figure 186, page 112
Oyster Mushroom
Edible
PILEUS firm to pliant, fleshy, white to ashy or brownish, 2-8 in. broad or
sometimes larger, fan-shaped to shell-shaped or elongated, usually marginate
behind, sometimes more or less circular and nearly centrally stipitate, convex,
sometimes depressed toward the stipe, smooth, moist, glabrous or minutely
tomentose toward the stipe, margin thin, inrolled, faintly striate when moist,
sometimes lobed and wavy, flesh thick, white, soft when young, becoming
tougher with age, odor and taste agreeable, lamellae broad, white or whitish,
close to subdistant, decurrent, extending down the stipe in vein-like lines with
varying amounts of converging and branching at the base, stipe very short,
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