162 THE NORTH AMERICAN SLIME-MOULDS 



1888. Stemonitis dictyospora Rost., Sacc. Syl. Fung., Vol, VII., p. 397. 

 1893. Stemonitis castillensis Macbr., Nat. Hist. Bull., Vol. 11, p. 381; 

 Plate X., Figs. 5, 5 a, 5 b. 



Sporangia crowded in colonies of unusual size, 4-8 cm., tall, rigid 

 18-25 mm., slender, erect, stipitate, black throughout; the columella 

 prominent, reaching nearly to the apex, abundantly branched, the 

 branches forming an intricate dark brown capillitium; the net large- 

 meshed several times the spore-diameter; the spores reticulate, spinu- 

 lose, clear violet, 7-8 /i. 



We here recover as is believed one of Rostafinski's best-described 

 species. Our material is from Nicaragua, by kindness of Professor 

 Shimek. Its relationship is with S. fusca where Rostafinski placed it. 

 The phrase describing spore-color is his. 



6. Stemonitis nigrescens Rex. 



1891. Stemonitis nigrescens, Rex, Proc. Phil. Acad., p. 392. 

 1911. Stemonitis fusca Roth, Lister, Mycetozoa, 2nd ed., p. 143. 



Sporangia gregarious, upon a common hypothallus, erect, small, 

 cylindric, stipitate; stipe black, extremely short, about half a milli- 

 metre; columella reaching the apex; capillitium violet-black, darker 

 near the surface, forming a complete superficial net at the lower part 

 of the sporangium only, elsewhere irregular or vanishing; spore-mass 

 nearly black; single spores violet-black under the lens, the epispore 

 spinulose and reticulate, about 8 /a. 



The author of this species remarks: "This species is noteworthy for 

 its comparatively short stipes, its very spinulose spores, and its black 

 or nearly black color, the slight violet tint being only apparent on 

 close inspection, especially in fresh moist specimens." 



It is a small but very beautiful form, at first sight to be mistaken 

 for a short S. fusca, though much more intensely black. The capil- 

 litium is concolorous, the inner network of rather few open meshes, 

 the outer of large hexagonal openings, the arcuate threads of which 

 are remarkable for the size, and especially the number, of the peridial 

 processes, as many as five or six sometimes appearing along one side of 

 a single mesh. The stipe is very short, and the columella runs as a 

 straight, gradually diminishing axis to the very apex of the sporan- 

 gium. Total height 3-5 mm. 



