HOTSON. — CULTURE STUDIES OF FUNGI. 275 



spherical or elongated bulbil with a fairly even margin, the central 

 cells of which soon become angular. In either case all the cells are 

 filled with conspicuous oil globules. At maturity there is no differ- 

 entiation of central and cortical cells, but all are uniformly filled with 

 food material, the central ones being larger, 28-35 n in diameter, 

 and more angular than those nearer the periphery. 



Papulospora pannosa n. sp. 



Plate 6, Figures 20-25; Plate 8, Figures 28-31; Plate 9, 



Figures 18-20. 



Mycelium white at first, becoming dark smoke-colored, 8-10 ^ 

 in diameter, somewhat shaggy; bulbils black, irregular, variable in 

 size and outline, sometimes 350 yu in diameter, but usually consider- 

 ably less; cells homogeneous throughout, 200-300 cells in surface 

 view; primordium, a group of intercalary or terminal cells. No coni- 

 dia observed. 



On laboratory cultures of rabbit and goat dung, and on corn-cobs 

 from Claremont, California. . 



Pure cultures of this fungus from about fifteen different sources 

 were obtained and grown on various kinds of media and the mycelium 

 from the different sources contrasted with each other, but thus far it 

 has not developed any other mode of reproduction than the bulbils. 

 This species is easily distinguished from most of the others by the 

 color of its bulbils. The only other black form is that of Cubonia 

 bulbifcra from which it differs in size and the character of its outline, 

 which is quite even and regular in the latter, as well by the fact that 

 the hyphae are black at maturity. 



The bulbils. — The mycelium which grows well on a variety of 

 media in tube-cultures, appears somewhat shaggy, is white at first, 

 gradually becoming dark smoke-colored, with prominent cross walls 

 which remain rigid when the cells collapse (Figure 31, Plate 8). The 

 hyphae which are 3-4 n in diameter when young and hyaline, gradually 

 increase in size until tiny are 8-10 /i in diameter, and have already 

 become dark in color at tin- time the black bulbils are produced. 

 During the formation of the latter, the hyphae become much dis- 

 torted, and divide into a series of short, somewhat inflated cells which 

 are separated by constriction at the septa (Figure 24, Plate 6), some- 

 what after the fashion of Cubonia bulbift /", but the successive cells of 

 these series are much more irregular and of greater diameter. These 

 enlarged cells send out lateral branches (Figure IS, Plate 9), from 



