DIANEMACE^ 247 



Order TRICHIALES 



Fructification sporangiate or plasmodiocarpous, the sporangia 

 stalked or sessile, gregarious or closely crowded, limeless; capillitium 

 of characteristically roughened or sculptured or rarely smooth threads, 

 free or attached to the sporangium wall, isolated or combined into a 

 net; spores generally bright colored, tinted with yellow, very rarely 

 dark. 



The distinguishing feature in this order is found in the peculiar 

 sculpture of the capillitial threads. This is suggested by the tubules 

 of Lycogala, though probably the resemblance is superficial only. The 

 individual threads, as in Trichia, are called elaters, from their probable 

 efficiency in spore dispersal. 



As here limited, the order is substantially coextensive with the 

 Calonemeas of Rostafinski. The course of differentiation may be 

 assumed to start with the Dianemaceaa, and to proceed through the 

 Perichaenaceae to the Arcyriaceae, and again, from the same starting- 

 point, through Prototrichia to the Trichiaceae. 



KEY TO THE FAMILIES OF THE TRICHIALES 



a. Capillitial threads slender, warted or spinulose, markings 



sometimes minute, threads rarely smooth b 



a. Capillitial threads coarser, marked by spirals, cogs or rings c 



b. Peridium usually single; capillitial threads solid, trans- 

 verse to the sporangial cavity, attached at one or both ends, 



or forming a net; markings minute or lacking Dianemace^e 



b. Peridium double; capillitial threads hollow, free or attached 



at one end, papillose or spiny, rarely smooth PericHaENACE,e 



c. Capillitium a distinct net, attached below to sporangium wall; 



markings various but never in the form of spiral bands Arcyriaceae 



c. Capillitium netted or of short, free elaters, marked by distinct 



spiral bands, rarely nearly smooth Trichiaceae 



Family DIANEMACE.E 



Sporangia pulvinate or plasmodiocarpous, sessile or substipitate ; 

 peridium usually single, thin, translucent, more or less iridescent; 

 capillitium attached, of solid slender threads with minute markings 

 usually arranged in one or more long spirals. 



KEY TO THE GENERA OF THE DIANEMACEjE 



a. Dehiscence lobate; capillitial threads jointed; spores dark 1. Lister ella 

 a. Dehiscence irregular; capillitial threads not moniliform; 



spores pale b 



b. Capillitial threads coiled, hair-like, simple, attached at 



base 2. Margarita 



b. Capillitial threads not coiled- ,.. c 



