250 THE NORTH AMERICAN SLIME-MOULDS 



wholly evanescent, except at the base, where persists the shallow, 

 colorless, often inwardly spinulose, plicatulate calyculus; stipe very 

 short or wanting; hypothallus thin but usually in evidence; capilli- 

 tium expanding to great length, forming an extremely flexile, plumose, 

 pendulose open network of pale ochraceous tint, the threads 3-4 /tx 

 in thickness, adorned with spinules, sharp edged transverse plates 

 sometimes rings, the surface especially marked by an indistinct reticu- 

 lation ; spore-mass buff or ochraceous, spores by transmitted light col- 

 orless, smooth or nearly so, 7-8 fx. 



This elegant species is not rare in undisturbed woods, especially 

 on fallen willows. The expanded capillitia are very soft and plume- 

 like, waving and nodding, very lightly attached below to the centre 

 of the peridial cup. The capillitium threads are rough, with irregular 

 spines and sharp-edged transverse plates, occasionally extending to 

 form rings. Resembles the first species somewhat in habit, size, and 

 the spinescent capillitium, but the resemblance is superficial only. 

 The color is at once diagnostic, and the capillitium is after all entirely 

 different. Not uncommon ; Canada to Mexico ; Maine to California ; 

 probably cosmopolitan. 



Bulliard's figure determines the synonymy. Persoon called the 

 form A. flavn, because Bulliard had missed the genus. 



4. Arcyria versicolor Phillips. 



1877. Arcyria versicolor Phillips, Grev., V., p. 115. 

 1877. Arcyria vitellina Phillips, Grev., V., p. 115. 



Sporangia gregarious or more or less crowded, pyriform or clavate, 

 dingy, olivaceous yellow, becoming reddish, stipitate; peridium mem- 

 branous, largely persistent below, where it gives rise to the deep, 

 goblet-shaped calyculus; stipe strand-like, weak, sometimes wanting, 

 concolorous with the peridium ; hypothallus prominent or venulose ; 

 capillitium only slowly expanded, bright golden yellow or orange, 

 the threads rather broadj about 4 /x in diameter, regular, even, ele- 

 gantly branching, adorned with abundant short spines or warts, very 

 small and evenly distributed, the whole net anchored in the bottom 

 of the vasiform calyculus ; spore-mass yellow, by transmitted light pale 

 or nearly colorless, smooth, about 10 /x. 



