288 
from .002 to .02 mm. in the other two dimensions. They are 
slightly enlarged at the base, roundly obtuse at the end and filled 
with granular contents. No stomata were discovered in the under- 
ground portion, but their place was supplied by numerous lenticels. 
The examination of a number of sections through this under- 
ground portion showed a row of phellogen cells extending around 
the stem, interrupted more or less in its regularity by frequent 
lenticels. Over that part of the surface where no lenticels occur 
three layers of cells had originated from the phellogen layer. By 
taking sections through a gynophore which has only begun to 
develop hairs, it is seen that this phellogen layer is the first layer 
of cells under the epidermis. The order of its development was 
not definitely determined, though there were indications that the 
first division was centrifugal and the two following centripetal. The 
diameter of the organ was thus increased by several layers of 
cells, as well as by the outward growth of the numerous lenticels. 
This latter fact also accounts for the unevenness of the surface of 
the subterranean portion. The cells derived from the phellogen 
retained the characteristic form and appearance of periderm. On 
testing for suberin, however, they were found to be entirely free 
from it, even in the older portions, when the hairs were beginning 
to die and separate from the cells below. 
The cambium of the bundles throughout this portion was gen- 
erally in an active condition, though it is not possible to state the 
exact portion of the organ where they lose their meristematic 
nature and change into phloem elements. 
Experiments with the Hairs of the Gynophore. 
Repeated experiments were made with plants bearing young 
gynophores which had not yet reached the ground when the plants 
were pulled up. Some were placed in a moist chamber and kept in 
the light; others were kept in darkness. In every case a narrow 
zone of hairs appeared in the course of about a week. This zone 
averaged three millimeters in length; its distance from the tip 
varied. On gynophores of stems kept in moist chambers in the 
light it was about eight millimeters; on those rolled in newspaper 
and kept but slightly moistened the zone of hairs was about one 
millimeter from the tip. 
