36 THE NORTH AMERICAN SLIME-MOULDS 



12. PHVSARUM THEJOTEUM Fries. 



1829. Physamm thejoteum Fries, Syst. Myc., III., p. 142. 



Sporangia very small, closely crowded on a delicate, more or 

 less visible hypothallus, often connate, but not superimposed, 

 sub-spherical, dull orange yellow or tawny ; peridium thin, vio- 

 laceous, covered with very minute yellow calcareous scales ; 

 columella none ; capillitium lax, sometimes almost wanting, the 

 nodules small, yellowish or brownish, occasionally confluent ; 

 spore-mass violaceous, spores by transmitted light, violet tinted, 

 smooth or nearly so, 6-7 /*. 



Not uncommon in the Mississippi Valley, where it sometimes 

 is passed by the collector as an immature form of some other 

 species. The appearance is very characteristic, unlike P. vires- 

 ccns in both habit, size, and color. Colonies are quite often 

 three inches in length. The most common habitat seems to be 

 rotten oak, especially fragments of charred logs, etc. 



Ohio, Illinois, Missouri, Iowa, Nebraska. 



13. PHYSARUM ATRUM ScJiweinitz. 



PLATE XV., Figs, i, i a, i b. 



1831. Physarum at mm Schw., N. A. F., No. 2299. 

 Physarum cinereum Ellis. 



Sporangia small, gregarious, confluent and clustered or 

 heaped, dull violaceous brown ; the wall thin, more or less 

 transparent, sprinkled with minute white angular flecks of lime ; 

 capillitium scanty, the calcareous nodes small and rounded- 

 elongate, white ; columella none ; spores violet brown, distinctly 

 warted, 10-12 p. 



Distinguished from everything else by its color and the small 

 size of the heaped sporangia. It is near Physarnm plum be ;/;;/, 

 but of different habit and with larger spores. It also resembles 

 some forms of P. cincrcitni, from which it is distinguished by its 

 more pronounced habit of aggregation and its general lack of 

 lime, as well as by the general color and appearance of the spores. 



Pennsylvania, North Carolina, Maryland. 



