PHYSARUM 67 



when longer tapering upward ; columella white, conical, sometimes 

 obsolete; hypothallus none; capillitium dense, but delicate, persistent, 

 a close network of hyaline threads, with white or yellowish nodes 

 sparingly thickened and calcareous, many without lime; spore-mass 

 brown'; spores by transmitted light, violet, minutely warted, 7.5-9 fi. 

 Plasmodium greenish-yellow. 



This species, very common eastward, rare west of the Mississippi, 

 is at once very beautiful and very variable. Its several phases have 

 been again and again observed and described too often by distinct 

 specific or varietal names. A form from New York, with long, 

 white stems and almost pure white sporangia, is P. albicans Peck. 

 Forms occur like P. albicans, but flushed wih rose throughout. From 

 New England, specimens sent Rostafinski were by him deemed 

 a variety of P. petersii Berk. & C, and called P. petersii var. far- 

 loiuii Rost. By this name the species has been generally distributed in 

 this country. N. A. F., 1120. Most gatherings of this species 

 have small, somewhat ochraceous, sporangia, and pale yellow, or 

 somewhat rusty, stipes. These latter, with somewhat heavier stem, 

 represent Physarum simile Rost. A form collected sparingly in 

 Iowa has short, white stipes and blue gray sporangia one-third larger 

 than observed in the eastern types. This was recorded, /. c, as P. 

 columbinum Macbr. ; name already in use. The spores in the Iowa 

 specimens are also a little larger, 8-10 fi. Pale cyanic and roseate 

 forms also sometimes occur in late f ruitings ; see next species. 



In all phases the persistent tenacity of the capillitium is a striking 

 characteristic well noticed by Fries (/. c, p. 101) : "Peridia a gleba 

 omnimo libera, dein tota diffracta, evanescentia, . . . capillitio 

 compacto forma servata persistente." The peridium, except a small 

 part below, all falls away, leaving the capillitium apparently intact; 

 crowded with spores. 



From England to Iowa ; Canada, south to Louisiana and Mexico ; 

 apparently, in one form or another, cosmopolitan. 



22. Physarum lilacinum Sturgis ^ Bilgram. 

 1917. Physarum lilacinum Sturg. & Bilg., Mycologia, Vol. IX., p. 3. 

 Sporangia gregarious, stalked, globose, erect, pale-lilac to pale 



