NATURAL HISTORY SURVEY 89 



Pileus 7.5 to 15 cm. broad; stem^.S to 10 cm. long, 2.5 cm. 

 thick; spores 12 to 13 x 7 to 8 p. 



Woods, near Chicago. Bates; Wyrick. 



PAXILLUS. 



Hymenophore continuous with the stem, decurrent; lamellae 

 membranaceous. scissile, somewhat branched and here and there 

 anastomosing behind, distinct from the hymenophore and readily 

 separating from it. Fleshy, persistent; margin of the pileus at 

 first involute, then continuously and gradually unfolded and 

 dilated, indeterminate. Spores dingy-whitish or ferruginous. 

 Paxillus involutes Fr. 



Pileus compact, convex or expanded, sometimes centrally 

 depressed, glabrous, viscid when moist, varying in color from 

 grayish or sordid buff to ferruginous or brownish-ochraceous, the 

 margin at first strongly involute and covered with a dense grayish 

 tomentose villosity; flesh grayish-white or pallid. 



Lamellae close, decurrent, branched and anastomosing behind, 

 whitish, then yellowish or subferruginous, becoming reddish- 

 brown or fuscous where cut or bruised, the interspaces venose. 



Stem equal or slightly thickened at the base, central or some- 

 times eccentric, glabrous, solid. 



Pileus 2.5 to 7.5 cm. broad; stem 2.5 to 7.5 cm. long, 8 to 16 

 mm. thick. Spores rust-color, ellipsoid or oblong-ellipsoid, 8 to 

 16 x 6 /x. (K.) 



On the ground in woods, Glencoe. September. 



AGARICUS. 



Stem annulate, distinct from the hymenophore; lamellae free; 

 spores brown or blackish-brown. Growing on the ground. 



Lamellae flesh-colored 1 



Lamellae at first whitish 3 



1. Pileus whitish or rufescent 2 



1. Pileus yellow A. comptulus. 



2. Flesh thick, stem stout A. campestris. 



2. Flesh thin, stem slender .4. silvaticiLS. 



Pileus smooth, shining-white A. silvicola. 



Pileus minutely brown-scaly A. placomyces. 



Agaricus comptulus Fr. 



Pileus convex then plane, obtuse, smooth or with an appressed 

 silkiness, yellow; flesh white, thin. 



Lamellae free, crowded, broadest in front, flesh-colored then 

 dark brown. 



Stem yellowish, stuffed then hollow, slightly thickened at the 

 base. 



Pileus 5 cm. broad; stem 5 cm. long, 4 to 6 mm. thick. 



Rich ground in a recently drained swamp. Palos Park. 

 April. In a garden, Wheaton. May. Spores ellipsoid, 12 x 7 /LI., 

 fuscous-umber, marked with minute spots of a darker color. 



