Seaver : North Dakota slime-moulds 579 



Macb 



Collected on rotten wood and distinct in the tubiferous spo- 

 rangia, which persist long after the shedding of the spores. The 

 sporangia occur in dense masses. 



LYCOGALACEAE 



Lycogala epidendrum (Bux.) Fries. 



The young phases of this plant are often met with in woods, 

 and the bright red color of the plasmodium of the forming spo- 

 rangia make them rather conspicuous objects. At maturity, how- 

 ever, the sporangia lose their bright color and become more 

 nearly the color of the substratum on which they occur. Said to 

 be the most common slime-mould in the world. 



TRICHIACEAE 



Arcyria incarnata Pers. 



The plants of this species are often found closely crowded on 

 rotten stumps, sometimes covering an area of several inches. At 

 maturity the delicate threads of the capillitium push out so that 

 the entire group of plants resembles rich flesh-colored velvet. 



Arcyria denudata (L.) Sheld. 



Plants resembling those of the preceding species but distin- 

 guished by the dull reddish brown color. The species was found 

 to be common but did not occur in such abundance as the preceding. 



Hemitrichia clavata (Pers.) Rost. 



Common on rotten wood and distinguished by the stipitate, 



cup-shaped remains of the sporangia containing the golden yellow 



capillitium. The twisted rope-like appearance, which is one of the 



characteristics of the genus, is revealed only by microscopic exam- 

 ination. 



Hemitrichia vesparia (Batsch) Macbr. 



At once recognized in the field as distinct from the preceding 

 by the dark reddish purple color of the sporangia. Several col- 

 lections made on rotten wood. The species is common. 



Trichia persimilis Karst. 



Rather common and widely distributed in North America. 



