414 BOTANICAL GAZETTE [JUNE 
Thus, the growing point of the bulb, lying in the seedling 1 or 
2 below the surface of the earth, is brought finally to the depth 
of 1oto15°. There it is met, as a rule, in the full grown speci- 
mens, in which the bulb has attained a large size ( fig. zo). An 
adult specimen produces about seven roots each year. Among 
these the difference in form and function disappears ; they are 
all of the same kind, about 5 ™™ thick, tapering soon to 3 or 2™ 
in diameter, and take up not a vertical, but more oblique course 
from the start. They are very long, covered with hairs, and 
form later on branches of the 1st and 2d degree, Their cen- 
tral cylinder is usually 13-archic, but the cortex reduced in 
abundance compared with that of the napiform roots of the half- 
grown specimens. The annual prolongation of the bulb-axis 
amounts in these old plants to 5 to8™™. So much are they 
carried down by the roots, however, that a full grown bulb, very 
_ superficially located, moved down in one year 2.5™. 
In connection with the study of Chloragalum I should like to 
e _ emphasize some facts concerning the behavior of the contractile 
roots, In Chloragalum, as in other species, the contraction does 
not z appear in the whole root at once. On the contrary, as each 
section of the root a short time after having finished its growth 
| length begins to shorten, necessarily the older basal sections 
nal ones ; also. the phenomena accompanying the contraction a 
ppea sooner in the base. Thus we see in the napiform roots 
galum that after a time the bark, smooth and lig 
commence their contraction earlier than the younger, more termi- 
Ma 
t a mes slack and wrinkled at the base, diminishing also i 
ter, and that by degrees this wrinkling and falling: down 
nces toward the tip over all the swollen basal region (ig. 9). e 
The roots of Chloragalum do not wait to commence ee 
ntr ction until they have attained their entire length, nor do” 
Zygadenus, Trillium, Lilium, Scoliopus, Ar Arisaema, NoF 
he species I know of, On the contrary, in all these . 
oud in | when the roots are aes short, perce 
