AGARICALES 129 



ing in clusters, often closely packed, from stumps and trunks 

 commonly of elm trees, and by its yellow-brown pileus and its 

 stem, which is darker and velvety at the base. 



C. radicata is also very common and may be easily recognized 

 by its distant lamellae and by its twisted stem ending in a root- 

 like base which descends from a bulbous or fusiform enlargement. 

 Both species are classed as edible. 



\f \f 



7\ i\ 



The various genera of the order Agaricales as constituted at 

 present show remarkable series of connecting forms combining 

 the various families as now recognized in an interminable network. 

 Not only are the three representative genera of the families Thele- 

 phoraceae, Polyporaceae and Agaricaceae connected by the inter- 

 grading species of intermediate genera, but each of the three 

 families is similarly connected with other representative genera of 

 all the other families of the order, and outliers connect with 

 various members of the following orders. 



A part of the difficulty involved appears to be due to the partial 

 failure to base genera on natural characters, too much use having 

 been made of artificial characters or superficial resemblances. A 

 part of the difficulty however is due to the fact that we have here 

 an extensive evolution of comparatively recent origin in which 

 very many of the steps of the progression are still in existence. 



A few of the details of this series of interrelations can be ex- 

 pressed by the following schedule : 



