32 



Genus 9. STEMONITIS 



In this genus, and in all those that follow it, there is no lime. 

 The fructification in Stemonitis is different from that of all 

 other genera mentioned in this paper except Comatricha, Ener- 

 thenema and Lamproderma, which are allied. In Stemonitis 

 there is a solid, black stalk which extends to almost the top of 

 the sporangium as a columella, except in certain confluent forms. 

 The brown capillitium springs from the part regarded as a 

 columella, the outside branchlets united to form a surface net 

 beneath a frail peridium, which latter is rapidly evanescent. The 

 species of the genus do not form sessile sporangia or plasmodio- 

 carps. The sporangia are narrowly cylindrical, and in some in- 

 stances reach a height of 20 mm. or more. They usually form 

 large colonies, either closely fasciculate or in smaller tufts, and 

 the color in most of the species is some shade of purple-brown. 

 Three species are abundant everywhere, and are distinguished 

 on spore and surface net characters, and somewhat by the 

 color. S.fusca is usually dark with a closely meshed surface net. 

 The spores have spines arranged in more or less reticulate fash- 

 ion. S. splendens is usually larger and not so dark, but more of a 

 purplish-brown color. The surface net is coarse, of very large 

 meshes, and the spores are faintly and closely warted without 

 reticulations. S. axifera has a reddish, ferruginous color, and 

 the surface net is close, like S. fusca, but the spores are almost 

 colorless, nearly smooth, and very small, 4-6/x diam. The spore 

 color of 5. axifera is an exception to the general rule of purple 

 tinted spores as mentioned earlier, the tint here being ferrugi- 

 nous. Around these three species are grouped several others hav- 

 ing different combinations of the characters mentioned; and 



EXPLANATION OF PLATES 



Plate I 



Fig. 1. Badhamia rubiginosa, X4 



Fig. 2. Physarum viride, XIO 



Fig. 3. Fuligo septica, XI 



Fig. 4. Leocarpus fragilis, X4 



Fig. 5. Diachea leucopodia, X4 



Fig. 6. Didymium squamulosum, X4 



Fig. 7. Stemonitis axifera, X3 



Fig. 8. Comatricha typhoides, X4 



