82 



appears that their order of nutritive value for this fungus, from poorest 

 to best, is 100, 43, 85, 60. Evidently a temperature of 43 is in- 

 sufficient to extract the nutrient proteids sufficiently, while 100 pre- 

 cipitates too many of them. While leucosin, a prominent proteid of the 

 embryo, is largely precipitated at 52 and a second coaguIuriTgOes down 

 at 82, no more is precipitated even by boiling (Osborne, 89). 



Graphs 1-4 (Fig. A), indicating conidial length on these four agars, 

 show that although the quantity of conidia produced varied materially, the 

 length and general variability are not greatly influenced by varying the 

 composition of the agar done in this case by change of temperature. 

 The conidial length of all these agars is, however, considerably less than that 

 on wheat shoots (cf. graphs in Fig. A and Fig. K). Graphs of conidial 

 breadth and septation on 43 and 60 agars given in Fig. B also show but 

 little influence of these agars on these two characters. A "Difco" corn- 

 meal agar, prepared according to my directions by the Digestive Ferments 

 Company, gave growth-characters almost identical with those of my 

 own 60 agar. On "Difco" beef-agar the conidia were short, and were 

 frequently deformed (M, 17.44.22, <r, 2.46.16, CV, 14.15.93). 



Plain agar (shredded agar only, 12 g. per liter). The fungus grew 

 rapidly, and in 6 days the colony was 35-45 mm. in diameter, but was 

 thin and colorless, with but few scattered conidia, and only 1 to 3, 

 or at the most 7 to 10, conidiophores per low-power field, except at 

 growth-inhibition points, as at the edge of the dish or where two colonies 

 approached each other, where the number of conidiophores rose to about 

 12 per low-power field. The conidiophores bore only one or two conidia 

 each. Conidiophores, conidia, and mycelium as well, were very faintly 

 straw-colored, much paler than on more nutrient agar. No zonation 

 occurred. No difference in rate or character of growth was observable in 

 1.3% and 2.6% plain agar. 



Growth on plain agar, on corn-meal agars, and on various combinations 

 of these nutrients. Corn-meal agar of various compositions was used, 

 12 c.c. to each Petri dish. On 25% corn-meal agar (made of 3 parts plain 

 agar plus 1 part ordinary corn-meal agar) the colony was much darker 

 and denser than on plain agar; was zoned more strongly; and conidia were 

 much more abundant, there being about 80 conidiophores per low-power 

 field, each with one to five conidia. The mycelium was much darker 

 than on plain agar. Colonies on 50% and 75% corn-meal agar showed 

 no essential difference from the colony on 25% agar. On full corn-meal 



