72 A Mojiograjfli of the Mijxiyjastres. 



Sub-sect. I. Stemonitae. 

 Stemonitis, Gled. 



Sporangia cylindrical, ovate, or globose, stipitate ; stem con- 

 tinuing into the sporangium as a columella of greater or less 

 length, and giving origin to numerous branches throughout its 

 length, which combine to form a dense, irregular network ; 

 wall of sporangium thin, soon disappearing, often with metallic 

 tints. 



Stemonitis, Gleditsch, Meth., p. 141 ; Rest., Mon., p. 193 (in 

 part); Cke., Myx. Brit., p. 40 (in part); Sacc, Syll., vii., pt. I., 

 p. 397. 



Comatricha, Preuss. in Sturm's Deutschl. (in part) ; , Rost., 

 Mon., p. 197 (in part) ; Cke., Myx. Brit., p. 47 (in part) ; Sacc, 

 Syll., vii., p. 894. 



The genus Comatricha was distinguished according to Preuss 

 by the globose or shortly elliptical sporangium from the species 

 of Stemonitis, a character shown by Rostafinski to be untenable, 

 hence the last-named author used characters suisposed to be 

 presented by the capillitium for the separation of the two 

 genera. In Comatricha the meshes of the network are arcuate 

 or curved, and not attached to the wall of the sporangium, 

 by short branches, whereas in Stemonitis the threads are not 

 arcuate at the surface, and the capillitium is attached to the 

 wall in numerous places by short branches. These characters, 

 not being constant, and furthermore overlapping in the two 

 genera, cannot be considered as of generic value, neither in my 

 opinion would they be so even if constant. 



Distrib. Scattered over temperate and tropical regions. 

 Species 23. 



A. Spores Uacldsh hroton in the mass. 

 § Spores wartccl. 

 Stemonitis fusca, Rost. (figs. 155 — 157 and 1G2— 104). 

 Densely grcyarioiLS, springing from a vxll-dccelopcd, broadly 



