24 Nebraska Agricultural Exp. Station, Research Bui. 7. 
so long and those of some pole beans so short that there is com- 
paratively little difference in height between the two sorts. In 
fact, if the taller sorts of bush beans are forced by favorable soil, 
moisture, etc., and the shorter kinds of pole beans are retarded 
by unfavorable conditions, the bush beans will ordinarily exceed 
the pole beans in height. (Compare the plants shown in Fig. 9.) 
Internode lengths will be considered in detail in a later section of 
this paper. 
GROWTH CURVES. 
In all races of Phaseolus vulgaris, so far as I have observed, 
growth is fairly rapid at the start but soon slackens materially 
as the food stored in the cotyledons becomes exhausted and then 
becomes increasingly more rapid as the young plant becomes 
well established. In general, therefore, the hypocotyl is longer 
than the epicotyl, which, in turn, is longer than the second^ inter- 
A 
B 
/ 
r 
0 2 
2 4 6 8 10 12 14 
Internode numbers. 
16 18 20 22 24 26 
Fig. 10. — Growth curves of the main axis of (A) a medium tall bush bean, 
Red Marrow, 3,330 (i), and (B) a medium short pole bean. Snow- 
flake, 3,425 (f). The dots, connected by lines to form these and all later 
growth curves, indicate the heights of mature plants at the upper end 
of the designate i internoies. 
1 Since the hypocotyl of a growing or mature plant cannot readily be 
measured, the epicotyl has been measured as the first internode. Thruout 
this paper, the first internode is regarded as beginning at the point of attach- 
ment of the cotyledons, the second at that of the primary leaves, the third at 
that of thejfirst trifoliate leaf, etc. 
