( -, THE AGARICACEAE CF MICHIGAN 



nulus and small glabrous pilei, are the result of unfavorable con- 

 ditions. Other varieties, like obscura, flava, glabra, radicata, bulb- 

 osa, etc., differ from the normal condition in the characters indi- 

 cated by their respective names. An abortive form occurs, doubt- 

 less parasitized like Glitopilus abortivus, by some other fungus 

 whose identity is unknown. This form consists of irregular round- 

 ish white masses composed of fungus mycelium. For a fuller ac- 

 count see N. Y. State Mus. Kep. 48, page 262. 



Armillaria mellea is of considerable economic importance. At 

 times it grows from living roots to which it is connected by black, 

 twine-like strands called Rhizomorphs. These are often found 

 even where no fruit-bodies are present, and before their connection 

 with this species was known, the strands were referred to an inde- 

 pendent fungus and called Rhizomorpha sub cortical is. These 

 strands extend under the bark of living roots and eventually injure 

 or kill the trees. The American A. mellea is safely edible. Large 

 quantities are collected by the foreign-born population of some 

 localities — Detroit and the mining regions of the Northern Penin- 

 sula; they are dried, and used for the table during the winter. The 

 taste is somewhat disagreeable, and many people do not think them 

 particularly palatable. 



Clitocybe monodclplia Morg. has been considered by some as a 

 variety of this species. It is, however, clearly separated by the char- 

 acter of the hyphae in the gills, which do not diverge as in the 

 genus Armillaria, but lie parallel between the subhymenial layers. 



C. PLEUROTOIDAE. Stem eccentric or lateral; gills decur- 

 rent. 



694. Armillaria dryina Fr.-Pat. 



Syst. Myc, 1821. 



Illustrations: Cooke, 111., PL 22G. (As Pleurotus.) 

 Patouillard, Tab. Analyt, No. 517. 

 Atkinson, Mushrooms, PL 32, Fig. 106, 1900. (As Pleurotus.) 



PILEUS 4-8 cm. broad, firm, convex-plane, floccose-tomentose at 

 first, in dry situations becoming scaly from the breaking up of the 

 Hoccose covering, white, scales darker iu age, margin at first in- 

 volute. GILLS decurrent, subdistant, attenuated at ends, broadish 

 i" the middle, white, not anastomosing behind. STEM eccentric or 

 lateral, 2-4 cm. long, 1-1.5 cm. thick, subequal, sometimes stouter 



