[Vor. 7 
12 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
Total 7 Piel 
et green 
wi, grams YN Corn or ap as ae 
Ml... /* Peas —... o Base lit A ss 
` N, pd 
s P. x yt 
4 ? Vv * A 
N A FN 
8 AS [ON 
Nn y à f A3 
7 LM A f 
je NY 8 M , te 
6 / M | 
3 j PA \ j | 
5 lle 5! N Base dine Whe tand Corn 
\ P \ ! 
4/ | \ 
4 E 
P 
2 
! 
QxO GF Go 
Ax Arta, Br0 BS feo Buy Bx red Bek, Bxk 2 zo 
Py 42 466 58 60 4$ 70 84 9+ %6 2% 3) 6g 60 
| $ 3 4 5 6 7 8 9 10 pd le B 
Fig. 1. Total green weight of wheat, corn (3), and Canada field peas (4), in solu- 
tions A and B, with variations—chiefly in H-ion concentration. 
of the solution; and even more favorable is the addition of small 
amounts of secondary phosphate. With corn, table u, the 
shift towards alkalinity in the A solution affords slightly in- 
creased growth, but it is an important fact that there is a rapid 
falling off in the neighborhood of Pu 6. This is approximately 
the H-ion concentration at which precipitation begins. With 
this crop, the B solution alone, solution B plus small amounts of 
alkali, and solution B with the addition of dibasic phosphate 
yield strikingly heavier than solution A. On the other hand, 
peas, under the conditions of these experiments, made maximum 
growth in the relatively acid solution A. 
