LIFE HISTORY OF TIMOTHY 17 
of the seasons when this characteristic of it has been studied. In 
some plats of ordinary timothy from which records were obtained in 
each of the four years from 1916 to 1919 there was an average total 
number of 759 shoots per square yard, whereas in plats of Xo. 3937 
grown under the same conditions there were 1.033 shoots per square 
yard. In the plats of ordinary timothy 14 per cent of these shoots 
were fertile, whereas in the plats of Xo. 3937 there were only 21 per 
cent of fertile shoots and a correspondingly larger percentage of 
sterile shoots than in the plats of ordinary timothy. 
It is evident from these records that there is an inherent tendency 
in some varieties of timothy to produce fertile shoots and sterile 
shoots in numbers and proportions different from those of other 
varieties. 
DESCRIPTION OF FERTILE SHOOTS 
At the base of all timothy shoots is the short proaxis ; next to it the 
haplocorm develops, and above this is the culm. A timothy shoot 
bearing a head is terminated by it. 
The different parts composing a timothy shoot bearing a head and 
the divisions of the stem are described in the accompanying diagram. 
The relative position of the parts of the stem is also shown graph- 
ically in Figure 4. 
(Proaxis 
Plaplocorm 
Culm 
Rachis 
Buds 
Inflorescence ihead) 
the proaxis 3 
The fertile timothy shoot, illustrated diagrammatically in Figure 
5, developed from a bud at the base of a shoot of the preceding 
year's growth. The proaxis is included between the points a and h. 
It is ordinarily composed of 10 to 15 or more nodes and non- 
elongated internodes. with a leaf at each node. By the time that a 
shoot has produced a head these basal leaves have become dry. It is 
from the nodes of the proaxis that the roots grow. In the axil of 
each leaf is a bud which may grow into a shoot when conditions be- 
come favorable. The leaves and buds grow alternately in two ranks 
on the proaxis just as they do on the upper part of the stem. A 
typical proaxis is illustrated in Figure 6. 
The proaxis makes its growth between the time when the shoot 
first develops from a seed or bud. usually in late summer or early 
autumn, and about the 1st of the following May. The haplocorm 
and culm, as has already been stated, make their growth after this 
time 6 (2o. p. 61-65). The length of the proaxis on 10 typical shoots 
collected from a 2-year-old meadow on June 3, 1914. varied from 
0.22 to 0.56 inch in length; the average length was approximately 
0.375 inch. 
5 C. V. Piper suggested the term proaxis for the basal part of the stem of grass - 
6 Evaxs. M. W. the life history OF timothy. George Washington University 
thesis, p. 31-38. 1920. Unpublished. 
4730°— 27 2 
