HEMITRICHIA 259 



E. TRICHIACE.^ 



Capillitium marked by spiral bands, sometimes scattered rings, 

 etc., the threads entirely free, or at least loosely branched, and 

 with free tips more or less nurqerous. 



Key to the Genera of the Trichiaceae 



A. Capillitium threads long, generally united to form a loose net, centrally 



attached, 



a. Sculpture spiral 1. Hemitrichia 



b. Sculpture reticulate 2. Calonema 



B. Capillitial threads shorter, entirely free, though sometimes branched. 



a. Threads, elaters, marked by spiral bands . . 3. Trichia 



b. Sculpture irregular or wanting .... 4. Oligonema 



1. Hemitrichia Rost. 



1829. Hemiarcyria Fries, Syst. Myc, III., p. 183 in part. 

 1873. Hemitrichia Rost., Versuch, p. 14. 



Capillitium a tangled net of more or less branching and anastomos- 

 ing fibres centrally attached ; the sculpture regular, of conspicuous 

 spirally winding bands or ridges; habit and color various. 



The species here associated are intermediate between Arcyria and 

 Trichia, resembling the former in the capillitial net and the latter in 

 thread-sculpture. Fries applied the name Hefniarcyrieae to a group 

 of trichias so-called, citing H. rubiformis as the first. In his Versuch 

 Rostafinski wrote Hemitrichia and afterward Hemiarcyria in the 

 Monograph. Massee combines the genera Arcyria and Hemiarcyria 

 under the former name. 



Key to the Species of Hemitrichia 



A. Plasmodiocarpous 



a. Plasmodiocarp net-like, yellow . . . \. H. serpula 



b. Imperfectly plasmodiocarpous, brown . . 2. H. karstenii 



B. Sporangia all distinct. 



a. Sessile; very short stalked 



i. Peridium hyaline, iridescent . . . . 3. //. ovata 

 ii. Peridium opaque 10. H. montana 



b. Stipitate, generally distinctly so; sometimes nearly sessile. 



i. Yellow or ochraceous. 

 * Stalk hollow. 



t Small, y^ mm., iridescent . . 6. H. leiocarpa 

 tt Larger, 1 mm., smooth but not iridescent 



