ECHINOSTELIUM 1 79 



mitted light it is seen to be yellow, translucent throughout, par- 

 tially filled with refuse matter, and the distribution of the refuse 

 makes the varied appearance seen by reflected light. The en- 

 larged, swollen mass seems to be a part of the stalk, not an attach- 

 ment, as sometimes it is seen between and separating the thicker 

 and thinner sections. The species is not rare in eastern conti- 

 nental North America, and may be found almost anywhere by 

 experienced collectors. 



Genus 21. ECHINOSTELIUM de Bary; Rost. Versuch 7. 

 1873. 



Sporangia stalked, very minute, about 50 ^ diam., white; 

 branches of the capillitium few, rising from the apex of a short 

 columella. 



A SINGLE SPECIES. 



1. Echinostelium minutum de Bar\ ; Rost. Mon. 215. 1874. 



Plasmodium colorless (Lister). Sporangia scattered or gre- 

 garious, stalked, white, globose, 40-50 /x diam.; sporangial wall 

 persistent at the base as a minute collar. Stalk slender, hyaline, 

 with scanty pale refuse matter, 0.4 to 0.5 mm. high. Columella 

 short, slender. Capillitium of a few arcuate threads, simple or 

 sparingly branched and anastomosing, with free spine or hook- 

 like branches. Spores colorless, smooth, 6-8 /x diam. 



Type locality: Europe. 



Habitat: On dead wood. 



Distribution: Florida, Iowa, Kansas, Massachusetts, New 

 York, Pennsylvania, Vermont, *West Virginia. 



Illustration: Lister, Mycetozoa ed. 3. pi. 128, figs. f^. 



The smallest of the known Mycetozoa. The sporangia are 

 often in fairly large colonies, and the white specks may be seen in 

 the field with a good magnifier. 



Genus 22. MACBRIDEOLA Gilbert, Univ. la. Stud. Nat. 

 Hist. 16: 155. 1934. 



Sporangia stipitate; stipe translucent, appearing hollow, ex- 

 tending into the sporangium as a columella; capillitium typically 

 lacking, although divisions of the columella may be found in some 

 sporangia; peridium membranous, translucent, evanescent or per- 

 sistent; spores brown. 



