LIFE HISTORY OF TIMOTHY 
11 
the upper unfolded leaf, which at that time extended above the tip 
of the upper elongated internode. In another series of measurements 
made on May 8 it was found that the average length of the elongated 
part of the stem, including the head, of 10 shoots collected from the 
tame meadow, was 0.2 inch. After that date the actual length of the 
elongated part of the stem gradually approached the figures just 
presented. 
In the early part of May. growth in length of the stems was com- 
paratively slow. Most of the growth in length took place during a 
period of approximately six weeks, from about May 23 to July 5. 
Growth continued, though less rapidly, until about July 10. 
In the same timothy meadow, the first florets were observed to 
be in bloom June 2-1. On June 30 the plants in the meadow were 
in full bloom and continued so on different days up to July 8. The 
data obtained in this field show, therefore, that growth of timothy 
JUNE 
JULY 
42 
40 
38 
36 
34- 
32 
30 
28 
i*26 
w 24- 
X 29 
12 
2£ 
17 24 
_J I [ ^_^Z 
- ^^zz^^zzz: zzizzi 
Fig. 2. — Curve showing time and rate of growth of timothy stems 
stems is comparatively rapid during the early part of the blooming 
period and that some growth in length continues up to about the 
time when the florets are through blooming. 
RELATIVE TIME WHEN DIFFEREXT IXTERXODES BECOME ELONGATED 
During the same period in which the data presented in the pre- 
ceding paragraphs were obtained, another series of measurements 
was made of the lengths of the different elongated internodes of 
timothy stems. Ten fertile shoots with heads were examined on 
each date. Since it was necessary to dissect the shoot in order to 
obtain an accurate measurement of each internode, a new group had 
to be used each time. Consequently, the data in Table 4 and the 
graph in Figure 3 show some slight irregularities in the lengths of 
the internodes on succeeding dates, which would not have occurred 
if it had been possible to use the same group of shoots for measure- 
ment each time. 
