HOTSOX. — CULTURE STUDIES OF FUNGI. 289 



bull)ils. Pure cultures from a half-dozen different sources were made 

 by the methods already described, and kept inuler cultivation on a 

 variety of media. 



The septate mycelium grows very slowly on nearly all substrata, 

 producing the best results on bran agar, and on sterilized fresh horse 

 dung on which it becomes somewhat flocculent. The i)rimary 

 mycelium grows on the top of the substratum, or just below the surface, 

 and sends up lateral branches into the air. It is these lateral branches 

 that produce its peculiar Aspergillus-like fructification. The primary 

 mycelium becomes very large, usually somewhat contorted and packed 

 full of granular material and oil globules. The hyphae, which an- 

 astomose reatlily often forming a sort of network, measure as much 

 as 11 /I in diameter, and some of the swollen lateral branches 17 // 

 (Figure 4, Plate 7). Occasionally, especially in the young hyphae, 

 there occur large swollen intercalary cells containing oil globules and 

 other food material (Figures 17-lS, Plate 7). These seem to be cells 

 for the storage of food. 



The bulbils. — The mycelium grows out e\enly in all directions from 

 the point of inoculation. In about tw^o or three W'eeks (on horse 

 dung, in about a week), small brownish-red spots appear near the 

 margin of the mycelial growth. These are young bulbils, and on 

 closer examination they are found to de\elop as follows. A short 

 lateral branch (Figures 2-3, Plate 7) well filled with nutrient material, 

 sends out branches which twine about each other. The former 

 sometimes coils at the tip but this seems to be incidental. These 

 secondary branches may come off near the base of the lateral branch 

 (Figure 3, Plate 7), and by twining about the primary hypha may 

 incorporate it in1;o the bulbil. >\Iore often, however, the secondary 

 branches come off a short distance from the hypha (Figures 2, 4, 6, 

 Plate 7), so that, especially in the early stages, it is evident that they 

 are on short pedicels. The secondary branches intertwine with each 

 other, and divide up into short cells, their lateral walls adhering 

 firmly to those of their neighbors and eventually forming a compact 

 mass of uniform cells. At maturity these bodies superficially resemble 

 true sclerotia perhaps more nearly than they do typical buli)ils, but 

 they are developed from a group of cells composing the primordia, 

 and not from a mass of interwoven hyphae from different sources. 

 They vary considerably in size and shape, some of them being nearly 

 spherical, aljout 100// in diameter; but most of them are irregular 

 in form, reaching in old cultures 570 X 750 fx. There is no differentia- 

 tion between the marginal cells and the central cells. Microtome 



