Stemonitis 149 



sporangium and rigid. Capillitium of purplish brown threads, 

 the principal branches springing at distant intervals from the 

 columella, at first almost simple, suddenly branching to form a 

 smooth surface-net with rounded or angular meshes of various 

 sizes, 20-70 m wide. Spores pale reddish purple, faintly and 

 closely warted, 7-9 fi diam. 



Var. Webberi (Rex) Lister, Mycetozoa 112. 1894. 



Stemonitis Webberi Rex, Proc. Acad. Nat. Sc. Phila. 1891 : 390. 1891. (N. Y. 

 B. G. no. 11767, type material.) 



Similar to the typical form but meshes of the surface-net 

 larger, 50-100 fi. 



Var. flaccida Lister, Mycetozoa 112. 1894. 



Stemonitis Tiibulina (?) Alb. & Schw. Consp. Fung. 102. 1805. 



Conatricha flaccida Morg. Jour. Cin. Soc. Nat. Hist. 16: 135. 1894. (N. Y. 



B. G, nos. 10549, 10574, authentic material.) 

 Amaiirochaete ferniginea Macbr. & Martin; Martin, Jour. Wash. Acad. Sc. 



22: 89. 1932. (N. Y. B. G. nos. 6898, 9962, type material.) 



Sporangia weak and poorly developed ; capillitium weak, often 

 lax, with a poorly developed surface-net or none; columellae ir- 

 regular, sometimes slender or tortuous; sporangia often collapsing 

 and leaving only columellae and spores. 



Type locality: Europe. 



Habitat: On dead wood. 



Distribution: Common and abundant throughout North 

 America; varieties not so common. 



Illustration: Lister, Mycetozoa ed. 3. pi. 121, figs. a-i. 



This species has several characters which distinguish it from 

 related ones. The capillitium is open, consisting practically of 

 only the supporting branches of the surface-net; the meshes of the 

 latter are large and not regular in size ; and the spores are remark- 

 ably constant in all their characters. It is subject to considerable 

 variation in the size of the sporangia, and the meshes of the sur- 

 face-net are usually large and small in the same sporangium. 

 Collections with more uniform small meshes approach 5'. herhatica. 

 Those with very large meshes are var. Webberi, and the same 

 variation of large and small meshes is found in the variety, so that 

 it overlaps with the typical form. The sporangia of var. Webberi 

 also vary in size, but otherwise there are no differences to separate 

 it specifically. 5. splendens is sensitive to conditions at the time 

 of fruiting, and many abnormal, erratic or weak forms are pro- 



