LIFE HISTORY OF TIMOTHY 
35 
HABITS OF GROWTH OF THE LEAVES 
The first indication of a new timothy leaf is when the tip of the 
blade extends up from within the folded sheath of the next older 
leaf. As the blade grows it continues to emerge from within the leaf 
below it. and at the same time it gradually unfolds. 
STAGE AT WHICH LEAF BLADES MAKE THEIR GROWTH IX LEXGTH 
A series of measurements was made of the blades of the three 
upper leayes of 14 elongated fertile timothy shoots. The data 
presented in Table 15 show that the blade of a timothy leaf has 
completed its growth in length by the time that it has emerged 
from within the sheath of the leaf below it. 
Table 15. — Average length of blades of timothy leaves at different stages of 
development 
Leaf length, (inches) 
State of blade 
Second 
from 
upper 
Next to L - 
upper < Lpper 
Just emerged . . ._ .. 
8.06 
8.13 
8.10 
7.35 
7.43 
7.41 
3.73 
Tip beginning to become drv_ 
3.69 
Entire blade dry . . .. ... . 
3.69 
PERIOD DURING WHICH TIMOTHY LEAVES REMAIN GREEN 
After a timothy leaf has completed its growth it remains green for 
a time, then begins to dry gradually from the tip downward to the 
base of the blade, and then downward to the base of the sheath. 
Records were made at intervals of three or four days during May, 
June, and July, 1916, of the time during which the blades of the 
same leaves referred to in Table 15 remained green or partially 
green. The data obtained are presented in Table 16. The total time 
during which the blades of the timothy leaves were entirely or par- 
tially green varied from about 50 to 60 days. Observations which 
have been made of other timothy leaves during the spring, summer, 
and fall indicate that in the growing season the usual period of time 
during which the blades of timothy leaves remain green is not 
greatly different from that indicated in Table 16. 
Table 16. — Avei'age length of time during which timothy leaf olades were 
entirely or partially green 
Position of leaf 
-n^-=r Da vs from 
Sss& i "sgjs, 
SESS safcp 
Days re- 
Days from 
quired for ^Pf^" 
complete 
drying of 
leaf blade 3 
of tip un- 
til leaf 
blade was 
dry* 
Second from upper leaf blade 
Next to upper leaf blade 
Upper leaf blade 
58.3 
56.0 
50.3 
1 Average number of days from time when tip of leaf appeared until the blade had entirely emerged. 
2 Average number of days from time when leaf blade had emerged until it began to dry at the tip. 
3 Average number of days from time when leaf blade began to dry until it was entirely dry. 
* Average total number of days from time when leaf blade first appeared until it was entirely dry. 
