[Vor. 8 
322 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
Growth and development in the acid cul- 
and development. 
This recalls the question 
tures, however, are decidedly greater. 
1 ae. ie 
E & T ul LE ET wu 
È TA b CA 
N BE NAA 
j^ INA 
Ñ 0 
; / \ { 
Lm ' 
é 20 / K Y 
, 
' ^ N 
, y 
+ a LR 
y — --- Im 
Py t 2 3 + = 6 7 a 9 /o 
Fig. 21. Puccinia graminis in M/5 mannite solution. 
suggested by Duggar ('01), of media stimulating germination 
and not growth, and vice versa. Maximum germination, as 
determined from my experiments, occurs within zones rather 
BO ise Pw Cae LN 
iig axe ‘eae ^N 
o apo ^ 
See LAS 
ie # a m MSN 
Ij- + 4 \ 
$ / / NOS 
Spo i / a 
v n d 
tj / j \ D 
S / / i 
a" / 7 , 
* 
LIN 
By ! 2 3 * € 7 8 9 /o 
Fig. 22. 
than at definite points. 
Puccinia graminis in 2 per cent bacto-peptone solution. 
L. saepiaria, like certain other species included within the acid 
group, proved very sensitive to an alkaline reaction, and while 
the limiting concentration on the acid side is somewhat lower 
