162 Rhodora [SEPTEMBER 
arvensis are elliptical 6-10 x 5-6.5 q. Those of A. Rodmani are usually 
subglobose. 
Agaricus Rodmani has sometimes been regarded as a form of A. 
campester [ A. campestris L.]. It differs from it, however, in having the 
flesh of the pileus thicker and firmer, the lamellae narrower and at first 
whitish, then pink, and the spores subglobose, while those of 4. cam- 
pester are elliptical and of nearly the same size as those of 4. arvensis. 
AGARICUS COMTULUS Fr. Pileus somewhat fleshy, plane to convex or 
obtuse, adpressedly fibrillose-silky, smooth, with thin soft flesh, becom- 
ing white ; lamellae free, rounded behind, crowded, soft, broader in 
front, flesh-color then rose, but not fuscous-flesh-color unless mature ; 
stem hollow, when young stuffed with floccules, subattenuated, even, 
glabrous, white, becoming somewhat yellowish; annulus medial, torn, 
fugacious, of the same color as stem; spores elliptical, 4.5 x 3.6 p. 
Pileus 2.5-3.75 cm. broad; stem 2.5-5 cm. long, 4-6 mm. thick. 
Agaricus comtulus has its pileus white, sometimes cream colored 
toward the disk; the lamellae exceed the pileus and change color 
with age; the stem has a somewhat enlarged base, and changes color 
to a light yellow. The only specimens I have seen were found grow- 
ing in thin grass under shrubbery by Dr. E. A. Burt. This species 
differs from A. campester in having a thinner pileus, shorter stem, and 
smaller spores 4.5 x 3.6 p. while those of A. campester are 6.5-7.5 X 
4.5 p. The lamellae are more beautiful in color than those of 4. cam- 
pester. 
AGARICUS DIMINUTIVUS Pk. Pileus thin, fragile, at first convex, 
then plane or centrally depressed, sometimes slightly umbonate, whitish 
or alutaceous, faintly spotted with small, thin, silky appressed brownish 
scales, the disk brownish or reddish-brown ; lamellae close, thin, free, 
ventricose, brownish-pink, becoming brown, blackish-brown or black ; 
stem equal or slightly tapering upwards, stuffed or hollow, smooth, 
pallid ; annulus thin, persistent, white; spores elliptical 5 x 3.5-4 p. 
Plant 3.5-5 cm. high, pileus 2.5-3.5 cm. broad, stem 2-4 mm. thick. 
Agaricus diminutivus is about the same size as A. comtulus and in 
some respects is perplexing to separate from it. The color seems to 
differ in the two. A. comtulus has a yellowish pileus; that of A. 
diminutiyus is of a reddish hue, usually, becoming paler near the 
margin, but sometimes uniformly tinged with red. The lamellae differ 
in the two species. Those of Æ. comtulus are flesh-color, then rose, 
and change to a fuscous flesh-color only when old, while the lamellae 
of A. diminutivus are brown or pinkish brown. The pileus of 4. 
comtulus is soft-fleshed and fibrillose-silky. A. diminutivus has a fragile 
