THE FUNGI WHICH CAUSE PLANT DISEASE 455 



elastic, often curved; gills annexed or sinuate, whitish, broad, 

 close; spores globose, 5-6 m- 



Parasitic on elm and maple or usually a saprophyte. 



Fig. 323. — Pluteus eervinus. After Clements. 



P. nidulans Pers. occurs on roots of trees in Europe. 

 Other questionable parasites are: P. atrocoeruleus Fr. on wil- 

 low; P. mitis Pers. on pine; P. corticatus Fir. on poplar. 



Armillaria Fries (p. 450) 



Fleshy, the substance of the pileus and stipe continuous ; annulus 

 fixed; gills usually attached, white; spores clavate, ellipsoid or 

 ovate, smooth. 



About sixty species. Figs. 325, 326. 



An extensive list of members of the genus, under the name 

 Agaricus, found growing upon woody plants has been compiled by 

 Wilcox.i"^ 



A. meUea (Vahl.) Quel."' '"• "' " 



Cap large, 3-15 cm. wide, usually honey-colored, but varying 

 through all shades of yellow to brown, typically marked with 

 small tufts of brownish or blackish hairs, especially toward the 

 center, though sometimes woolly or entirely smooth, margin often 

 striate, convex to expanded; stem tall, stout, 3-15 cm. by 6-20 mm., 

 whitish, yellowish, or brownish, especially below the ring, smooth 

 or scaly, hollow or stuffed, ring usually thickish and conspicuous, 



