160 
seeds were ripened (as is usually the case). All branches not ter- 
minated with flower clusters, cast off their tips at well marked 
scars. Rhus copallina sheds a tip about 15 mm. long, consisting 
of three or four leaves with very hairy, strong petioles and very 
small and narrow, almost needle-like leaflets, 3-4 mm. long. Khus 
aromatica (Fig. 18) casts off its leaves at a point a little above the 
base of the petiole; the portion remaining attached to the stem is 
rather appressed, and hides the subtended bud during its earlier 
development. The terminal scar is found at the end of a round, 
rod-like tip, which may be produced quite a distance beyond the 
point of attachment of the uppermost remaining leaf. Rhus radi- 
cans has terminal scaly buds. 
Robinia Pseudacacia (Fig. 3). The terminal scar is somewhat ir- 
regular, owing to the angulate character of the branches. In con- 
sequence of shrinking, subsequent to the falling off of the tip, the 
terminal scar is quite puckered up, as is also the case with Gledit- 
schia triacanthos. The figure shows the top of the branch still at- 
tached, but withering, and the position of the scar is already indi- 
cated by the fact that the yellow color of the withering part stops 
abruptly at a plane bounding the green portion further down which 
is to remain. Even before the slightest withering has commenced, 
it is already possible to see at what node the plane of separation is 
to be by the fact that whereas the last leaf of the remaining por- 
tion develops rapidly. into a full sized leaf, the next succeeding leaf 
which is to fall off shows retarded growth at a very early stage, 
while the tip is still green. 
During the first week of August all the tips of the higher branches 
had fallen off. This was true also of the lower branches, where the 
tree was fully developed. Occasionally, however, the lower 
branches were more vigorous, and were still continuing growth, or 
were preparing to also cast off their tips. From one of these lower 
branches the figure was taken. In young growth, or in fresh 
shoots from cut down stumps, the tips of the branches were often 
present in the middle of August, but in the middle of September 
all the tips seemed to be shed. In the axils of the leaves are little 
-raised circular scars, left by axillary buds which are cast off ata 
very early stage of their development. In the figure these are 
shown in all except the lowest axil. In very vigorous shoots 
