266 Mycetozoa of North America 



made by Mr. Hugo Bilgram at Philadelphia, and the Quebec one 

 by Mr. Rispaud and me at Duchesnay. Otherwise the only 

 reported gatherings are from England and Scotland, where it 

 has been found frequently. The stalks and minute size are the 

 only pronounced characters. There is nothing of importance in 

 the wall, the capillitium, or the spores to distinguish it from other 

 American species of the genus Perichaena. It seems to be con- 

 stant in its habitat on dead leaves. 



Family III. MARGARITACEAE 



Sporangia usually sessile; sporangial wall single, rarely of two 

 layers in Dianema, smooth, usually translucent; capillitium con- 

 sisting of solid threads, either coiled and hair-like, or nearly 

 straight and attached to the sporangial walls, simple or branching 

 at acute angles. 



Threads of the capilHtium profuse, coiled. 45. Margarita 



CapilHtium of nearly straight slender threads attached 



above and below to the sporangial wall. 46. Dianema 



Threads of the capillitium marked with spiral thickenings, 



stout below, penicillate and slender above, attached 



above and below to the sporangial wall. 47. Prototrichia 



Genus 45. MARGARITA Lister, Mycetozoa 203. 1894. 



Sporangia sessile; sporangial wall translucent; capillitium a 

 profuse coil of hair-like, nearly simple, solid threads, with indis- 

 tinct attachments to the sporangial wall. 



A SINGLE SPECIES. 



1. Margarita metallica (Berk.) Lister, Mycetozoa 203. 1894. 



Physarum metallicum Berk. Mag. Zool. Bot. 1: 49. 1836. 

 Margarita pictoviana Moore, Trans. N. S. Inst. So. 12: 196. 1910. 



Plasmodium watery white (Lister). Sporangia solitary or 

 clustered, globose, sessile on a narrow base, 0.5 to 1 mm. diam., 

 or pulvinate and forming plasmodiocarps, pearl-gray or copper- 

 colored, shining iridescent; sporangial wall membranous, single, 

 yellowish, translucent. Capillitium a profuse coil of very long, 

 elastic, flexuose, solid, gray or yellowish threads 0.5-1 ^ diam., 

 increasing in some parts to 2 ju, scarcely branching in normal 

 developments, with few attachments to the sporangial wall or 

 almost free, marked with a very lax spiral band of minute spinules. 



