LIFE HISTORY OF TIMOTB. ^ 
-which make a vigorous, healthy 
growth may apparently continue to 
grow, at least under favorable con- 
ditions, for an indefinite period. 
THE SEEDLING 
A timothy seedling as it appears 
a few days after the seed has germi- 
nated is illustrated in Figure 1. 
AVhen a timothy seed germinates, 
first the coleorhiza or root sheath 
expands. The plumule, inclosed in 
the coleophyll, next appears (13. 
p. 21^-25). ^Soon afterwards the 
radicle or primary seminal root (a 
to <?, fig. 1) breaks through the 
coleorhiza. Filaments closely re- 
sembling root hairs develop on the 
coleorhiza and also upon the minute 
epiblast (25, p. 57-60). There is 
usually but one seminal root in 
timothy, though sometimes a second 
one develops. 
From the nodes at the base of 
the primary shoot of the plant 
another set of roots appears (at &, 
fig. 1). These roots, as well as 
those which grow from the base of 
other shoots which develop later, 
are called nodal or adventitious 
roots. 
The organ connecting the seed 
and the base of the primary shoot 
is the mesocotyl (a to b, fig. 1). 
Koots rarely if ever grow from the 
mesocotyl of timothy, though short 
appendages resembling root hairs 
commonly develop from it. 
The leaves of the growing bud 
of the plumule are inclosed within 
the sheathlike coleophyll (b to c. fig. 
I). 3 Within a few days after the 
coleophyll has developed, the tip of 
the first leaf blade emerges and 
gradually unfolds (c to d, fig. 1). 
There is considerable difference 
of opinion amc 
plant morphol- 
3 Coleoptile has teen used more commonly 
than coleophyll. Both are Greek derivatives. 
Coleoptile is compounded from the words 
meaning " sheath " and " feather " ; coleophyll 
from " sheath " and " leaf." Coleophyll is 
evidently the name which hest describes this 
part of the timothy plant. 
Fig. 1. — A timothy seedling (enlarged) : 
a to e. Seminal root or radicle ; a to 
b. mesocotyl; b to e. coleophyll; c to 
d, upper part of first leaf with blade 
