120 THE NORTH AMERICAN SLIME-MOULDS 



This, one of the most beautiful species in the whole series, is re- 

 markable for the variations which it presents in the fruiting phase. 

 These range all the way from the simplest and plainest kind of a 

 plasmodiocarp with only the most delicate frosting of calcareous 

 crystals up through more or less confluent sessile sporangia to well- 

 defined elegantly stipitate, globose fruits, where the lime is some- 

 times so abundant as to form deciduous flaky scales. The hypothallus, 

 sometimes entirely wanting, is anon well developed, even continuous, 

 venulose, from stipe to stipe. The capillitium varies much in abun- 

 dance as in color ; when scanty, it is colorless and in every way more 

 delicate, when abundant, darker in color and sometimes with stronger 

 thickenings. 



D. fuckeliaiium Rost., as shown in A^. A. F., 2090, and in some 

 private collections, seems to be a rather stout phase of the present 

 species; the stipe is more abundantly and deeply plicate, is sometimes 

 tinged with brown, and the capillitium is darker colored and coarser 

 than in what is here regarded as the type of the species; but withal 

 the specimens certainly fail to meet the requirements of Rostafinski's 

 elaborate description and figure, Mon., p. 161 and Fig. 154. 



D. effusum Link, probably stands for a sessile form of this species, 

 but Link's brief description (1816) is antedated by the much better 

 one of Albertini and Schweinitz, /. c. 



Generally distributed throughout the wooded regions of North 

 America, from New England to Nicaragua, and from Canada to 

 California. Not uncommon about stable-manure heaps, in flower 

 beds, and on richly manured lands. July, August. 



Nicaragua specimens not only show a continuous vein-like hypo- 

 thallus, but have the peridia often confluent, the columellae in such 

 cases confluent, the stipes distinct. Furthermore, the largest spores 

 reach the limit of 12.5 /x, and perhaps the larger number range from 

 10-12.5 fx, and all are very rough. This corresponds with D. macro- 

 spermum Rost., which is distinguished, says the author {Mon., p. 

 162, opis), "chiefly by the large and strongly spinulose spores." 

 However, the same sporangium in our Central American specimens 

 yield spores 9.5-12.5 fi, a remarkable range. So that D. macro- 

 spermum on this side the ocean, at least, cannot be distinguished from 



