THE AGARICACEAE OF TROPICAL NORTH 

 AMERICA— II 



William A. Murrill 



The genera treated in the present paper show a strong contrast 

 to most of those in the first article of this series, both as to the 

 number of species found in our tropics and the general informa- 

 tion regarding them. This is chiefly due to the fact that tough 

 forms growing on wood above ground are better adapted to trop- 

 ical conditions than fleshy forms, especially the larger ones, grow- 

 ing in the soil, where air is scarce and bacteria and moulds abound 

 in the rainy season, and where extreme conditions of heat and 

 dryness prevail during the dry season. The fleshy forms are 

 also difficult to collect and preserve, and require good field notes 

 to make them really valuable for study. 



These genera are all abundantly represented in temperate re- 

 gions, some of the species being the most common ones found in 

 our forests, but tropical conditions appear to offer an almost 

 impassable barrier to them, Lepiota alone excepted. The fol- 

 lowing simple key shows how these genera may be readily 

 distinguished. 



Volva and annulus both present. i. Leucomyces. 



Volva alone present. 2. Vaginata. 



Annulus alone present. 

 Lamellae free. 



Spores hyaline, tinged with brown in a few species. 



Pileus dry, usually scaly. 3. Lepiota. 



Pileus viscid, smooth. 4. Limacella. 



Spores green when fresh, brown in herbarium 



specimens. 5. Chlorophyllum. 



Lamellae attached. 



Stipe fleshy. 6. Polymyces. 



Stipe cartilaginous. 7. Chamaemyces. 



i. Leucomyces Batt. Fung. Hist. 27. 1755 

 Venenarius Earle, Bull. N. Y. Bot. Gard. 5 : 450. 1909. 



This genus includes the species usually known under the name 

 Amanita, which name is properly a synonym of Agaricus, as 



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