2 BULLETIN 1450, U. S. DEPARTMENT OE AGRICULTURE 
the United States Department of Agriculture and the Ohio Agricul- 
tural Experiment Station. For a few years previous to 1915 this 
station was located at New London, Ohio. In 1915 it was transferred 
to its present location at North Ridgeville, Ohio. 
GEOGRAPHICAL DISTRIBUTION 
The genus Phleum includes about 10 species inhabiting the Tem- 
perate Zones of both hemispheres (£, p. 102). 2 Of these species only 
one, Phlewnv alpinum L., is native of North America (18, p. 140) ; it 
is of little economic importance. Phlewni pratense L., which is native 
to Europe and northern Asia, and which now commonly grows wild 
as well as . in cultivated fields throughout the humid parts of the 
northern United States and southern Canada, was introduced proba- 
bly from Europe (29, p. 122). 
ECONOMIC IMPORTANCE 
Timothy grown alone or in mixture with clover is the most im- 
portant meadow grass in the northeastern part of the United States. 
It is also grown extensively in the more humid parts of the North- 
west, and to some extent on irrigated land there. According to the 
Fourteenth Census of the United States, timothy in 1919 was grown 
alone on 10,941,347 acres, and in mixture with clover it was grown 
on 19,349.405 additional acres (U, p. 796-797). 
DEFINITIONS 
Since some of the terms used in this discussion have been employed 
elsewhere with different meaning and others are new, it seems de- 
sirable to define the exact way in which they are used here. 
Seedling. — The young plant which develops directly from the seed. 
The young plant is regarded as a seedling up to the time when 
lateral shoots appear, or until internodes of the primary shoot be- 
come elongated. 
Plamt. — Includes all growing shoots which have developed from 
a single seed or from the detached vegetative part of another plant. 
In a plant several years old there may be a number of groAving 
shoots, or groups of shoots, connected by the nonliving, more or less 
disintegrated basal parts of shoots which were growing in preceding 
years. These separate yet closely associated snoots and groups of 
shoots, which have had a common origin even though they are not 
vitally connected, are together regarded as a single plant. 
Shoot. — Includes a stem with its attached roots, leaves, buds, and 
inflorescence. 
Each bud is a potential branch or lateral shoot. The term " shoot " 
may be applied from the time when the bud has expanded and both 
leaves and roots have developed. Shoots which produce inflores- 
cences are fertile; those which do not produce inflorescences are de- 
scribed as sterile shoots. 
Innovation. — The name applied to a young shoot which has de- 
veloped from a bud up to the time when branches develop on it, or 
until its upper internodes begin to become elongated. 
2 Serial numbers (italic) in parentheses refer to " Literature cited," p. 53, 
