BY SELF-ADAPTATION TO THE ENVIRONMENT. 261 
found in the Deserts. Many have very small capitula. Thus the 
head of Jfloga spicata is six tenths of an inch across; that of 
Leontodon hispidulum and of Brocchia cinerea being one quarter ; 
while that of Artemisia monosperma is only one eighth of an 
inch. As the flowers of Composite are generally more or less 
fertilized by one another on the same head, a process practically 
equivalent to self-fertilization—which is also equally common— 
there is nothing surprising in finding Desert Composite setting 
seed without the aid of insects. 
One or two special points of degradation may be mentioned. 
In Cotula anthemoides, Brocchia cinerea (Pl. XII. fig. 20), and 
Franceuria crispa the customary quinary symmetry has become 
quaternary. In the first-named plant the outer florets have a 
very rudimentary corolla with a jagged border. In Senecio 
egyptiacus (Pl. XII. fig. 18), Franceuria crispa (Pl. XII. fig. 19), 
Tfloga spicata, &c. the stigmas remain included within the 
anther-tube, just as occurs in the Common Groundsel; in Senecio 
e@gyptiacus the two stigmas being situated quite at the bottom of 
the tube. In all the specimens examined the pollen was early 
shed and the stigmas matured early. -Artemisia monosperma has 
almost microscopically minute florets, and, as might be anticipated, 
it is completely self-fertilizing, the stigmas being tufted (Pl. XII. 
fig. 17). This is the only genus of Composite the pollen of 
which, according to Mr. C. F. White’s researches, is smooth ; but 
I find that it is so also in Centaurea egyptiaca (Pl. XII. fig. 22). 
CampanuLaces&.— Wahlenbergia cervicina is a small plant of 
a few inches in height, and cleistogamous (PI. XII. fig. 23). On 
cutting the corolla vertically, the curled stigmas are seen to lie in 
the midst of the anthers, and are of course directly pollinated by 
them (PI. XII. fig. 24). A species of Campanula, C. sulphurea, 
is found near the great petrified forest a few miles east of Cairo. 
The corolla is inclined to be funnel-shaped rather than cam- 
panulate (Pl. XII. fig. 25). It is of a pale yellow colour, about 
three quarters of an inch in length. The anthers shed their 
pollen early and fall down, as is usual in this genus; but the 
style and stigmas are remarkable in that the former has few col- 
lecting hairs (Pl. XII. fig. 26), except just below the stigmas; while 
these latter are quite mature and pollinated at an early stage. 
BoraGinex.—Of the genus Heliotropium tour species, and of 
Anchusa three are found in the Deserts. The flowers are very 
small. Those of H. luteum are about one sixth of an inch in 
