Murrill : Agaricaceae of Tropical North America 73 



toward the margin, viscid, 3-4 cm. broad ; spores 7X5/*; stipe 

 whitish, glabrous above the annulus, squamulose below, 3-4 cm. 

 long. 



Doubtful Species 



Stropharia melasperma (Bull.) P. Karst. Bidr. Finl. Nat. Folk 

 32 : 489. 1879. Reported from Costa Rica by Patouillard. 



Stropharia stercoraria (Fries) Quel. Champ. Jura Vosg. ill. 

 1872. Probably confused with S. semiglobata in tropical 

 America, as it is elsewhere. 



12. Agaricus L. Sp. PI. 1 171. 1753 



Pratella S. F. Gray, Nat. Arr. Brit. PI. 1 : 626. 1821. 

 Psalliota Quel. Champ. Jura Vosg. 107. 1872. 



This genus, distinguished among brown-spored gill-fungi by a 

 fleshy stipe, free lamellae, and the presence of an annulus, has 

 received much attention from mycologists because of the im- 

 portant edible species in it. The different species are usually 

 not very well characterized, being much the same in shape and 

 color and differing very little in spore characters. Moreover, the 

 variations in some species are quite confusing. Judging from 

 the wealth of material at hand, it would seem that the inhabitants 

 of tropical America are fully as well provided with safe, appetiz- 

 ing food supplied by members of this genus as are their brothers 

 farther north. 



Species occurring on dead roots of bamboo i. A. bambusigenus. 



Species occurring among humus in woods or thickets. 



Pileus grayish with brown scales; stipe 4 mm. thick. 2. A. angustifolius, 

 Pileus fawn-colored with reddish shades ; stipe 8 



mm. thick 3. A. subsilvicola. 



Pileus brownish, darker brown on the rounded umbo ; 



stipe 5-7 thick 4. A. Johnstomi. 



Pileus purplish-incarnate or rose-colored. 



Pileus 5 cm. broad 5. A. cinchonensis. 



Pileus* 10 cm. broad 6. A. Venus. 



Species occurring in grass on lawns or in fields. 

 Pileus white, without squamules. 



Annulus simple 7. A. campester^ 



Annulus of two parts, radially split below .... 8. A. pratensis. 

 Pileus white or yellowish, with brownish squamules. 



Pileus 5-10 cm. broad 7. A. campester. 



