OF BACCHARIS GENISTELLOIDES 695 
On the third the main shoot withered; and one of the buds 
produced a branch on which the wings are apparently normal, 
but on which three small leaves have been found. Four other 
plants produced leaves on branches that retained their wings. 
The apogeotropic habit of the secondary branches made another 
experiment possible. A plant on which the main branch had fallen 
from its own weight and on which there were a number of such 
upright shoots was layered —that is, had its main stem covered 
with earth. After allowing the branches to rest in this condition 
for some time, the connection of the vertical shoots with one 
another and with the main stem was severed. However, although 
all the shoots flourished and grew into separate plants, none pro- 
duced the leaves, 
To sum up briefly the most important points brought out in 
_ this investigation : 
1. Baccharts genistelloides is a plant remarkably well adapted 
by the loss of leaves, by the position of the wings, and by the 
coverings of the cutin, wax and hairs, to withstand a high degree 
of both dryness and insolation. 
2. The glandular hairs differ from the hairs previously de- 
scribed in the Compositae in the possession of chlorophyl, and the 
Whip-hairs in being biserial. 
3. The early acquisition of lignin in the bast of the stem, and 
of mechanical tissue in the wings, gives to the plant its character- 
istic rigidity, and at the same time necessitates a short period of 
elongation. : 
4. The leaves found in any given portion of the stem on the 
older parts of the plant resemble closely the leaves of other species 
of Baccharis. 
5. The leaf differs from the wing in structure in showing 
marked dorsiventrality, which is absent in the latter. 
6. While the wings are directly continuous with the margins of 
the scales and of the leaves when present, and while they follow 
the phyllotaxy, they are to be considered morphologically as 
lateral-vertical expansions of the stem and not as “‘decurrent 
leaves,” ; 
7. The shoots have been shown to be markedly apogeotropic 
and positively phototropic. 
