A frican and Madagascar Flowering Plants . 349 
outward component, and is therefore counteracted by the 
staminal tube. 
In fact, in order to produce explosion, an insect must in- 
sert its proboscis between the thickened carinal edges, and so, 
by separating them, allow them to slip over the sides of the 
staminal sheath. If this is done by a needle an explosion 
occurs and pollen is scattered in all directions. This necessity 
of separating the carinal edges explains the fact that Meehan 
saw bumble-bees, hive-bees, and sand-wasps visiting the flowers 
without causing explosion. The Bombus at Philadelphia 
however could not have understood the flowers, as Delpino 
saw Bombus italicus causing explosion of /. macrostachya and 
being much alarmed thereby. (See also No. 346 Muller.) 
Sutherlandia fruteseens, R. Br. 
See Annals of Botany, vol. iv, 1890, p. 268. 
Lessertia pulehra, Sims (Figs. 66-68). 
The calyx-tube in this flower keeps the alae and carina 
together. The shape of the latter is peculiar ; its lower 
margin follows exactly the shape of the ovary and style, 
while its two upper margins are in contact above form- 
ing a vertical narrow edge ( a — Fig. 68). On depression 
pollen emerges as a ribbon-like streak all along this edge 
(a — b). The stigma is protected by a circle of long stiff 
almost upright hairs which are depressed by the weight of 
the insect. 
Clitoria heterophylla, Lam . (Fig. 69.) 
The flowers are blue and, like those of C. Mariana , in- 
verted. (Trelease, ‘American Naturalist,’ vol. XIII, Nov. 1879.) 
The vexillum is large and forms a broad alighting place 
for insects : pollen is very early shed on a brush of hairs 
which covers the inner face of the style ; the alae and carina 
are united and move together so that when they are forced 
upwards by the insect, the pollen-covered style protrudes. 
The nectary is peculiar, in fact so far as I know unique in the 
order ; it consists of a reflexed collar-like ridge rising from 
the staminal tube and lying like a saddle upon the ovary. — 
