Apr. 7,1923 
Temperature Relations of Eleven Species of Rhizopus 2 1 
nodosusy nigricans, and arrhizus had for their upper limits 43° to 44°, 
33.5®, and 42®, respectively; Lendner (ij) gives 30® to 35® as the 
optimum for tritici and 30® to 40® as that for chinensis; while Bruderlein 
(j) states that maydis makes its optimum growth at 39®. This is con¬ 
siderably higher than that obtained by the Vvriters. No explanation 
for this apparent difference can be given. 
Fig. 14.—Graph showing the increase of growth of Rhizopus nigricans for consecutive 24-hour periods. 
Graphs (fig. 13 to 23) were constructed to show the variation in the 
growth rate at different temperatures for successive 24-hour periods. 
The ordinates represent diameter increase in millimeters while the ab¬ 
scissas represent successive 24-hour periods after exposure to a given 
temperature. An inspection of these graphs shows that for most of the 
fungi the maximum rate of growth was attained during the second 24- 
hour period, the exceptions being delemar and chinensis, which reached 
their maximums one day later. The data for nodosus, although not alto- 
