154 Mycetozoa of North America 



11. Stemonitis axifera (Bull.) Macbr. N. A. Slime-Moulds 120. 

 1899. 



Trichia axifera Bull. Herb. Fr. pi. 477, fig. 1. 1789; Bull. Champ. 118. 1791. 

 Stemonitis ferruginea Ehrenb. Sylv. Myc. Berol. 25. 1818. 



Plasmodium white, rarely pale yellow. Total height 7 to 

 20 mm. Sporangia narrowly cylindrical, in dense and often large 

 clusters, stalked, usually curved, rusty brown. Stalks black, 3 to 

 7 mm. high, rising from a membranous hypothallus. Columella 

 ending below the summit of the sporangium. Capillitium with a 

 smooth and usually close surface-net, connected with the col- 

 umella by few stout branches, and composed of rather firm threads 

 bounding rounded meshes, which are usually small although vary- 

 ing in size. Spores very pale ferruginous, nearly smooth or 

 faintly warted, 4-6 n diam. (Plate 15, fig. 7.) 



Var. Smithii (Macbr.) Lister, Mycetozoa ed. 2. 150. 1911. 

 Stemonitis Smithii Macbr. Bull. Nat. Hist. S. U. Iowa 2: 381. 1893. 



Sporangia 3 to 6 mm. high, with surface-net of very slender 

 threads, often uneven, the inner capillitium well developed. 



Type locality : France. 



Habitat: On dead wood. 



Distribution: The typical form is common and abundant 

 throughout North America; var. Smithii not so common. 



Illustration: Lister, Mycetozoa ed. 3. pi. 119, figs, e-g, as 

 S. ferruginea. 



This common species, so easily recognized by its rusty brown 

 color, and pale, almost colorless, small spores, requires little com- 

 ment. It is subject to extreme variation in size, and var. Smithii 

 appears to be but a small phase developing from a weak Plasmo- 

 dium. The Plasmodium of 5. axifera is usually reported as white, 

 but on a number of occasions I have seen typical sporangia of 

 large size developing from a yellow one. 



Genus 17. COMATRICHA Preuss, Linnaea 24: 140. 1851. 



Sporangia globose, cylindrical, or obovoid, gregarious or scat- 

 tered, or clustered, stalked (except in C. Rispaudii) ; sporangial 

 wall evanescent (subpersistent in C. typhoides); stalk extending 

 within the sporangium as a columella; capillitium consisting of 

 numerous threads usually combined into a more or less uniform 

 network, not uniting to form an even, regular surface-net. 



Type species: Comatricha obtusata Preuss. 



