HEMITRICHIA 2OI 



The species here associated are intermediate between Arcyria 

 and Trichia, resembling the former in the capillitiai net and 

 the latter in thread sculpture. Fries applied the name here 

 adopted 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 species of Hemitrichia. 



A. Plasmodiocarpous. 



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



b. Imperfectly plasmodiocarpous . . . .2. H. karstenii 



B. Sporangia all distinct. 



a. Sessile ; some very short-stalked. 



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



ii. Peridium opaque 10. H. montana 



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



i. Yellow or ochraceous. 



* Stalk hollow. 



f Small, \ mm., iridescent . . . 6. H. leiocarpa 

 ft Larger, i mm., smooth but not iridescent. 



1 . Free ends more or less abundant, 8. H. clavata 



2. Free ends none . . 9. H. stipitata 

 ** Stalk solid 7. //. intorta 



ii. Not yellow. 



* Ruby red .... 4. H. -vesparium 

 ** Copper-colored . . . . 5. H. stipata 



i. HEMITRICHIA SERPULA (Scop.} Rost. 



PLATE III., Figs. 4, 4 a, 4 b. 



1772. Mucor serpula Scop.. Fl. Cam. II.. p. 493. 



1794. Trichia serpula (Scop.) Pers., Rom. N. Bot. Mag., I., p. 90. 



1875. Hemiarcyria serpula (Scop.) Rost., Man., p. 266. 



Fructification plasmodiocarpous, often covering several square 

 centimetres in extent, terete, branching freely and usually every- 

 where recticulate, rusty, tawny, or bright yellow ; the peridium 

 thin, transparent, with irregular dehiscence ; hypothallus none ; 

 capillitium variable, a tangle of long yellow threads, sparingly 

 branched, free everywhere, spinulose, the free tips spinose, 



