39 



others having three or more, so that the spirals are diagnostic. 

 T. persimilis is another common form and in the group with 

 reticulated spores, but the poorest member in that respect as 

 the reticulation is not continuous, but broken or partly replaced 

 by warts. The species forms small groups of crowded, globose, 

 sessile sporangia. Near to it and fairly common is T. Javoginea 

 which has lengthened, sessile sporangia, also densely crowded. 

 The elaters are much broader than in T. persimilis, and the 

 spores are beautifully reticulated with continuous bands show- 

 ing from three to five meshes to the hemisphere. Among the 

 brown forms, 7". contorta is the only one that forms sessile spo- 

 rangia, and it is common. 



Genus 19. HEMITRICHIA 



There is only one important difference between the genus 

 and Trichia. The capillitium consists of a more or less elastic 

 network of branching threads, parts of which are attached to 

 the sporangium. This has spirals like in Trichia and occasion- 

 ally spines. The same yellow colors predominate. //. vesparium 

 is the only red species on red stalks with red capillitium and 

 spores. The sporangia are usually combined in clusters and have 

 firm walls, and often distinct lids. When empty the cluster 

 appears like a miniature wasp's nest, from which the species 

 takes its name. //. clavata is a yellow form on brown stalks. The 

 sporangia are turbinate or funnel-shaped, and the yellow capil- 

 litium protrudes therefrom in an expanding mass. H. serpula 

 produces elongated, branching, and netted plasmodiocarps ex- 

 tending 1-8 cm., and yellow throughout. The three species can 

 be readily recognized. 



Genus 20. ARCYRIA 



The species of Arcyria form stalked sporangia, the upper 

 part of the wall evanescent, but persisting below as a deep or 

 shallow cup. The capillitium is attached to this cup, more or 

 less, and arises therefrom as a tall, expanded, netted mass. The 

 capillitium is variously ornamented with spines, warts, cogs, 

 or half rings, but not with distinct spirals as in Trichia and 

 Hemitrichia. The predominating colors are red, yellow, and 

 white. Among the red forms, A . denudata is extremely abundant. 

 The cup is shallow and the capillitium is firmly attached to it 



