58 THE NORTH AMERICAN SLIME-MOULDS 



any diderma. The outer peridium is reflexed exactly as in some 

 species of that genus; is yellow without, white within, and withal 

 long persistent. The capillitium of course distinguishes the species 

 instantly as a physarum. By the size of the spores it is distinguished 

 from the species preceding. This being a decisive specific character 

 the synonymy prior to Rostafinski is somewhat uncertain. The spe- 

 cific name adopted by the Polish author is therefore approved, al- 

 though perhaps not the earliest. 



Rare. The only specimens thus far are from Tennessee and Lou- 

 isiana. 



11. Physarum mortoni Macbr. n. s. 



Plate XX., Figs. 2, 2 a. 



Sporangia gregarious, clustered but distinct, sessile small, about 

 .75 mm., bright yellow, peridium double. The outer rough, break- 

 ing up into comparatively few rather large deciduous scales, the inner 

 peridium white, calcareous, both persisting below to form a distinct 

 cup; capillitium lax, the nodes white, large, angular; columella none; 

 hypothallus none ; spores distinctly rough, dark brown with the usual 

 purple shadow, 10-12 /a. 



A very distinct little species related, no doubt, to P. contextum, 

 but different in habit. It is never crowded, shows no plasmodio- 

 carpous tendencies, while the outer peridium is generally deciduous 

 except at the base and falls in flakes. 



Collected several times in the Three Sisters Mountains of Oregon 

 by Professor Morton E. Peck. 



12. Physarum brunneolum {Phillips) Mass. 



Plate XX., Figs. 7, 7 a. 



1877. Diderma brunneolum Phillips, Grev., V., p. 114. 

 1888. Diderma brunneolum Phill., Saccardo, Syll. Fung., No. 1292. 

 1892. Physarum brunneolum Phill., Massee, Man., p. 280, Figs. 221-222. 

 1894. Craterium pedunculatum Lister, Mycetozoa, p. 71. 

 1911. Physarum brunneolum Mass., Lister, Mycetozoa, 2nd ed., p. 63, Pi. 

 69, Fig. a. 



Sporangia scattered or gregarious, but not crowded, sessile, glo- 



