Development of Cassytha fitjormts, L. 411 
vessels are normally quite empty. Through their bordered 
pits from the adjoining smaller cells, hernioid protoplasmic 
swellings protrude, which even in the earliest stages show a 
delicate wall. This phenomenon is so frequent that one can 
scarcely cut a section without finding at least one instance 
of it. Not only the bordered pits, but apparently any of the 
pitted elements show it. The small undifferentiated wood 
cells are rich in protoplasm and contain healthy nuclei. 
They communicate with the large pitted vessels by the 
closely packed pits. One cell may have as many as six such 
openings, and through each of these the protoplasm may 
ooze. There is apparently no regularity, as the figures 
demonstrate. Frequently the entire nucleus, which in such 
cells always lies on the side by which the protoplasm is 
escaping, squeezes its way through the much smaller pit, 
and when it is through, again rounds out to its normal form. 
The entire vessel may thus be completely blocked by immi- 
gration of cells, which have nucleus and cell wall, though 
this latter seems of a highly plastic nature, being round when 
not impeded, but admitting of indentation by other buds 
that may come in contact with it. The small pitted cells 
into which tyloses form show no large connection between 
their ends, while the pits are oval, not bordered. 
The protoxylem shows the usual spiral tracheae. 
The leaves are small, scale-like and comparatively func- 
tionless. They are scattered and occur in a one-third spiral, 
six to eight cm. apart. The young green seedling has green, 
sessile scales, one to one and a half mm. long and with a 
broad attachment. They have stomata on both surfaces 
and are supplied with three veins. Some have long jointed 
hairs on their edges, probably surviving remnants rather 
than functional organs. The older leaves lose their green 
color, become quite membranous and dried at the tip, but 
retain their stomata. 
In the seedling stem the earliest distinguishable trace of the 
stelar system is a ring of five xylem elements, each asso- 
