Perichaena 261 



regularly, and with short or long spines on the capillitium. The 

 brown covering of refuse matter may be partially or completely 

 absent in some parts of a colony. This is seen in many other 

 species, and is due to the particles washing away by moisture 

 during formation of the fruiting bodies. In a collection made on 

 Long Island, New York, a few of the sporangia have large, dark 

 warts, similar to those on the wall of P. minor var. pardina. The 

 species is connected by intermediate forms with the common 

 phase of P. corticalis, which dehisces by lobes. 



2. Perichaena vermicularis (Schw.) Rost. Mon. App. 34. 1876. 



Physarum vermiculare Schw. Trans. Am. Phil. Soc. II. 4: 257. 1832. 

 Ophiotheca vermicularis (Schw.) Massee, Mon. 134. 1892. 



Plasmodium watery white, yellowish white, or rose-red (Lis- 

 ter). Sporangia scattered, sessile, subglobose on a narrow base, 

 0.2 to 0.5 mm. diam., or more often forming slender, curved, 

 netted or ring-shaped plasmodiocarps, ochraceous yellow, pale 

 umber, or grayish; sporangial wall of two layers, the outer more 

 or less charged with dark granules and occasionally with angular 

 crystals of lime, closely combined with the membranous, papil- 

 lose, inner layer; in some phases the outer layer is not distinguish- 

 able in the upper part of the sporangium. Capillitium a profuse 

 network of sparingly branched yellow threads 2-4 fi diam., rough 

 with minute scattered warts and irregular constrictions. Spores 

 yellow, minutely warted, 10-15 /x diam. 



Type locality: North Carolina. 



Habitat: On pithy stalks, plant stems, and bark. 



Distribution: Colorado, *Iowa, Kansas, New Jersey, New 

 York, *North Carolina, Ohio, ^Ontario, *Oregon, *Panama. 



Illustration: Lister, Mycetozoa ed. 3. pi. 187, figs. a-c. 



This species is rarely collected by others, although probably 

 common enough, as I have found it frequently on pithy stalks 

 and stems. The yellow phase with net-like plasmodiocarps and 

 minute spines or warts on the capillitium is readily identified. 

 The darker forms, usually on bark, may have short, curved plas- 

 modiocarps only, and are sometimes difficult to distinguish from 

 phases of P. chrysosperma when the spines on the capillitium of 

 the latter are short. They are somewhat intermediate, connect- 

 ing the two species. Forms with lime on the outer wall are occa- 

 sionally found. 



