38 BULLETIN 1450, TJ. S. DEPARTMENT OF AGRICULTURE 
July 28, more than one month later, the average length of the same 
heads was 3.95 inches. This shows that timothy heads practically 
complete their growth in length by the time they have emerged 
from within the upper leaf sheaths of the shoots. 
LENGTH OF TIMOTHY HEADS 
Webber has shown that there is a variation in the lengths of the 
heads of the plants of some different varieties of timothy (4#, p. 
349-351). 
The length of heads of plants growing in a comparatively rich 
soil, and especially in new meadows, is much greater than of plants 
growing under less favorable cultural conditions. 
On Julj 19, 1916, all the heads on shoots growing in a typical 
square-foot area in a 3-year-old timothy meadow were measured. 
The lengths of the heads ranged from 0.4 to 3.8 inches, and the 
average length was 1.7 inches. From another meadow, sown in the 
preceding season, a number of typical heads were collected; they 
were from 3 to 4.8 inches long, and the average length was 3.7 
inches. From along the edge of another field, where soil conditions 
were very favorable for a large and vigorous growth of the plants 
growing there, one head (an exceptionally long one) was collected 
which measured 11.2 inches in length. The lengths of the heads 
in the two former groups are more nearly typical of the heads of 
timothy plants growing in ordinary meadows. 
TIME WHEN TIMOTHY FLORETS BLOOM AND SEEDS MATURE 
Timothy florets bloom in northern Ohio during the latter part of 
June and the early part of July. Within a few weeks, late in July 
or early in August, the seeds mature. The time when the florets 
bloom and the seeds mature varies slightly in different years, be- 
cause of different seasonal conditions (5, p. 330-333). Figure 7 
shows that there is also some difference in the time when plants of 
different selections or varieties bloom and mature in the same season. 
THE FLOWERING HABITS OF TIMOTHY 
Observations of the flowering habits of timothy have been made at 
the timothy-breeding field station in nearly every season since it has 
been established. During the period from June 22 to July 7, 1914, 
a special study was made of this subject. Timothy plants were ex- 
amined each night at intervals of two hours from 6 p. m. until 8 
o'clock the next morning (9, p. 299-309). 
When a timothy floret blooms, the anthers emerge first and then 
the stigmas. The anthers do not dehisce until after the stigmas 
of the same floret have been exposed for some time (20, p. 35). Any 
movement of the stem soon after the anthers have dehisced will 
cause the pollen to float away through the air in a miniature cloud. 
On the morning of June 28, 1922, exceedingly large numbers of 
timothy florets were in bloom. The air was very quiet until a little 
past 7 o'clock, when a breeze arose. When gusts of wind moved the 
steins of timothy plants growing in near-by plots the pollen could 
