African and Madagascar Flowering Plants . 343 
the basal lobes of the vexillum, and also thickened so that 
the union of the two is still more close. 
Podalyria euneifolia, Vent. (Fig. 25.) 
Similar to the other species, but with the edges of the 
carina in front folded one within the other so as to form a 
more perfect tubular cavity for the style and pollen. This 
species (as probably all the others) is visited abundantly by 
Xylocopa caffra, which is very common near Cape Town. 
Liparia sphaerica ; L. (Figs. 27-30.) 
This flower is the most modified of any of the South 
African Leguminosae . The lowest calyx segment is very 
large (13 lines long and 7 lines broad) ; the four lateral 
calyx teeth are tucked under the revolute edges of the 
standard (see Fig. 27). The vexillum also is very rigid and 
has a strong arched claw. The alae are rather narrow with 
their superior surface spread out horizontally, while at their 
ends they are rolled together round the tip of the carina 
through half a turn, so as to form a conical bag, out of which 
the tip of the carina protrudes. An insect standing on the 
vexillum can effect cross-fertilisation just as well or possibly 
better than when entering by the carina ; firsts because the 
vexillum being rigid and supported by the upper calyx- 
segmenls cannot yield to its weight, and, secondly , because 
the carina and alae, being supported by the lowest expanded 
calyx-segment, cannot give bodily but simply allow the tip of 
the carina to slip a little further through the alae ; the carina, 
being thus squeezed by the latter, will at first allow the pollen 
to emerge as a thin thread, and finally permit the stigma to 
appear. I devoted many afternoons to the discovery of the 
insect which fertilises this rare flower, but I was unable to find 
it. Xylocopa could, however, do this. 
Priestley a villosa, Thunb. 
The basal lobes of the vexillum come w r ell down over the 
sides of the flower. The alae and carina are connected by, 
first , a shallow depression of the former fitting on to a similar 
B b 
