Paxillus involutus
Scientific name: Paxillus involutus (Batsch) Fr.
Derivation of name: Involut- means "rolled up or "inrolled"
referring to the cap margin.
Synonym: Agaricus involutus Batsch
Common name(s): Poison Paxillus; Brown roll-rim.
Phylum: Basidiomycota
Order: Boletales
Family: Paxillaceae
Occurrence on wood substrate: Saprobic/ectomycorrhizal;
solitary to several on the ground or on and near decaying wood,
in conifer and mixed wood; July through November.
Dimensions: Caps 4-12 cm wide; stipes 4-10 cm long and
1.5-2 cm thick.
Cap: Brownish, covered with matted hairs, sometimes spotted;
dry to tacky in wet weather; margin remaining inrolled.
Gills: Decurrent; yellowish-olive, bruising reddish-brown; easily
separable from cap; forked or pore-like near stalk.
Spore print: Yellowish-brown.
Stipe: Smooth; colored like cap; staining darker brown where
handled.
Veil: Absent.
Edibility: Poisonous.
Comments: Although the mushroom is eaten in some places,
there are reports that ingestion results in a gradual
hypersensitivity leading to kidney failure.
Figure 1. Note the inrolled margin. Photo © William
Roody.