109 



STBMONITIS.] STEMONITACE^. 



Sporangium-wall somewhat persistent, columella about half the 

 height of the sporangium. (18) Lamproderma. 



Fig. 26. — Lamproderma irideum Mass. 

 a. Group of sporangia. Magnified 2^ times. 

 J. Sporangium deprived of spores, showing capil- 

 litium. Magnified 25 times. 



Sporangium-wall partly evanescent, persistent in the form of 

 minute discs at the apex of the rigid capillitium threads. 

 Columella short or hardly' evident. (19) Olastoderma. 



Fig. 27. — Clastoderma Debaryanum Blytt. 

 a. Group of sporangia. Magnified 10 times. 

 J. Sporangia deprived of spores, showing capillitium. 



Magnified 64 times. 



Fig. 27. 



Genus 15.— STEMONITIS Gleditsch, Meth. Fung., p. 140, tab. 

 iv. (1753). Sporangia cylindrical, stipitate, fasciculate; the stalk 

 extending within the sporangium to near the apex as a columella ; 

 capillitium formed of numerous threads radiating from all parts 

 of the columella and combined into a loose net-work, the ultimate 

 branches united into a superficial net attached to the evanescent 

 sporangium-wall. 



KEY TO THE SPECIES OF STEMONITIS. 



A. Spores grey, violet-grey, or rufous-violet : — 



a. Spores spinulose, more or less reticulated, surface net of 

 capillitium with angular meshes. ' 1. *S'. fusca 



h. Spores minutely warted, almost smooth, surface net of 

 capillitium with usually roiinded meshes — 



Meshes of surface net of capillitium 20 to 100 jj, or 

 more wide ; sporangia forming on wood. 



2. aS*. splendens 



Meshes of surface net of capillitium less than 20 ft. 

 wide ; sporangia forming on herbaceous plants. 



3. S, herhatica 



