Arcyria 247 



the inner side. Stalk cylindrical, 0.3 to 0.8 mm. long, red, rarely 

 white, arising from a membranous hypothallus, filled with spore- 

 like cells. Capillitium an elastic network of freely branching 

 reddish or yellow threads 5-8 /x diam., usually massed, and con- 

 nected with the tube of the stalk by one to three long basal threads 

 which are about half the breadth of the others or less, and may be 

 up to 10 mm. in length; threads triangular or oval in cross section, 

 usually thicker on one side, and marked with transverse bars or 

 reticulations arranged in a lax spiral, on the other two sides 

 marked with a broken reticulation or with warts, often spinulose 

 throughout; free ends with rounded or pointed tips are not infre- 

 quent. Spores pale red or ochraceous, faintly and closely warted. 

 9-12 ij. diam. (Plate 14, fig. 3.) 



Type locality: Austria. 



Habitat: On dead wood. 



Distribution: California, Colorado, *Indiana, Maine, Massa- 

 chusetts, Mississippi, New Hampshire, New Jersey, New York, 

 *Nova Scotia, *Ohio, Ontario, *Oregon, Pennsylvania, Quebec, 

 *South Carolina, *Washington. 



Illustration: Lister, Mycetozoa ed. 3. pi. 173. 



This species is subject to much variation in all respects. Two 

 phases are usually seen among the American gatherings, a large 

 one, and a smaller one which is more common, but they are con- 

 nected by intermediate forms. The small phase was described 

 by Peck as ^. macros pora. The sporangia after appearing require 

 nearly six days to mature properly, and are subject therefore to 

 vagaries of the weather, which may affect them and cause varia- 

 tions in the capillitium such as free ends, bulbous thickenings, or 

 spines. I have made many collections of the small phase in Pike 

 County, Pennsylvania, and watched the development from the 

 first appearance of the sporangia until maturity. The species 

 fruits from May to November, and occasionally, parts of a colony 

 will be yellow in color. Ileterotrichia Gabriellae is regarded as an 

 abnormal development of the small phase (see Mycologia 29: 

 393). A. nodulosa, described on a single collection from Pennsyl- 

 vania, seems to be another one. The description of the latter 

 reads like a description of one of the abnormal developments 

 which have been affected by moisture or colder weather during 

 the formation of the sporangia. 



