LIFE HISTORY OF TIMOTHY 33 
The length of the leaf blades on timothy shoots in early spring 
is less than the length of the blades which develop a few weeks 
later. This is illustrated by the following records of the average 
length, on different dates, of the green and partially green leaf 
blades on a typical shoot in the spring of 1914. 
On April ±8 the average length of all of the green leaf blades was 
2.4 inches ; on May 2 it was 2.4 inches ; on May 16 it was 3.9 inches ; 
and on May 29 it was 4.8 inches. 
The blade of the upper leaf on the culm is usually shorter than the 
blades of the other leaves on it. This is shown by the results of 
measurements presented in Table 12, which were made in June, 1916, 
of the lengths of the sheaths and blades of the four upper leaves on 
five typical culms from a timothy meadow. 
Table 12. — Average length of sheaths and blades of the four upper leaves of 
five elongated timothy shoots 
Average length 
(inches) 
Location 
Third from upper leaf-. 
Second from upper leaf. 
Next to upper leaf 
Upper leaf 
THE NUMBER OF LEAVES ON TIMOTHY SHOOTS 
Since one leaf grows at each node of a timothy shoot the num- 
ber of leaves, nodes, and internodes of the shoot are the same. As 
has already been shown in Table 9, the total number of internodes 
and leaves which develop during the life of a shoot depends largely 
upon the length of its growing period. On the elongated part of 
fertile shoots there are usually five to seven, most frequently six 
leaves. On the elongated part of sterile shoots there are ordinarily 
more leaves than on fertile shoots, and the number of leaves on 
the former increases as long as they continue growth. 
NUMBER OF LEAVES GROWING AT ONE TIME ON A TIMOTHY SHOOT 
The leaves of timothy plants differ in their period of growth from 
the leaves of deciduous trees and shrubs. On the latter class of 
plants leaves unfold in the spring and remain green until the fol- 
lowing autumn. On timothy plants leaves appear at any time and 
during the growing season each leaf remains green for a period 
of about two months or less. New leaves continue to appear in suc- 
cession at comparatively regular intervals, then after remaining 
green during their usual period they become dry in the same order 
of succession in which they appeared. 
The number of leaves with entirely or partially green blades on 
a timothy shoot at any particular time does not usually vary to 
any great extent from the time that the seedling or innovation has 
become fully developed until some time after the internodes of the 
shoot begin to become elongated. On most of the shoots for which 
4730°— 27 3 
