148 THE NORTH AMERICAN SLIME-MOULDS 



Sporangium wall rough with blunt spine-like processes, otherwise 

 as Diderma. 



One species, op. cit., p. 432, P. echinocephala v. Hohn. 



Java. Might as well be called Diderma echinocephalum, one 

 would think. Structure is that of Leangium. The striking character 

 is a surface modification of the outer peridium, according to the 

 description. 



Order II 



STEMONITALES 



Capillitium present, thread-like, arising in typical cases from a well- 

 developed columella; spores in mass, black or violet-brown, more 

 rarely ferruginous. 



Key to the Families of Stemonitales 



A. Fructification aEthalioid, capillitium poorly defined; columella rudimentary 



or none AMAUROCHiCTACEiE 



B. Fructification of distinct sporangia, capillitium well defined ; the columella 



generally prominent, long and abundantly branched throughout 



Stemonitace^ 



C. Sporangia distinct; capillitium developed chiefly or only, from the sum- 



mit of the columella LAMPRODERMACEiE 



A. AMAUROCH^TACE^ 



Fructification aethalioid, an inch or two in diameter, in form vary- 

 ing with the habitat and place ; capillitium dendroid, consisting of 

 rather stout branches which rise irregularly more or less vertically 

 from the hypothallus, branch repeatedly, often anastomose to form a 

 network, especially toward the periphery; spores black. 



A single genus — 



1. Amaurochaete Rostafinski 



1873. Amaurochaete Rost., Versuch., p. 8. 



The genus A maurochaete as defined by Rostafinski and the genus 

 Reticularia as represented by R. lycoperdon Bull, stand, the expres- 

 sion, perhaps, of not dissimilar histories. Whether in regressive or 



