African and Madagascar Flowering Plants. 351 
depression is to cause the vertical section of the alae to 
become circular instead of elliptical^ and this causes the 
carina to separate widely above leaving free egress to the 
pollen-covered style which is only slightly curved. Visitors : 
— Apis mellijica , ab., also Lepidoptera (cf. P. diver sifolius ) 
described by Foerste, Macleod, No. 151). 
Vigna triloba, W alp. 
This form shows a further advance in structure on 
Phaseolus adenanthus , as the vexillum is connected with the 
alae in three ways : first , by the thickened basal lobes of its 
wing, which fit in between the alar claw and auricle ; secondly , 
by a pulley-like thickening in the middle line of the vexillum 
(just where the broad part of its blade begins), and which 
holds the superior edges of the alar blades together ; and, 
thirdly , by another pair of thickened pegs which are developed 
between the other thickenings and run forwards and inwards, 
fitting upon the outside of the auricles of the alae. On com- 
parison with P. adenanthus , it is easily seen that in this 
species the single pulley-like thickening in the front of the 
vexillum has become double, so that the auricle of the alae is 
still made to work in a groove between the basal and medial 
thickenings of the vexillum. The vexillum-claw has on its 
lower sides two raised edges, which clasp the odd stamen (this 
is similar to that of Phaseolus ) in its broad part very firmly. 
The style emerges in this species through a small orifice at 
the end of the carina. 
Vigna angustifolia, Bth. 
The flowers are very unsymmetrical. The vexillum has 
the usual turned-in edges on its claw to clasp the odd stamen, 
and on its expanded limb there is a conical peg to the right 
of the midrib, about 4 lines from the base. The peculiar 
want of symmetry in the alae and carina seems due to the 
style, which begins (after the horizontal ovary) by a vertical 
portion, and is then suddenly bent over to the left at right 
angles to its course, being at the same time twisted, so that 
the upper surface becomes wholly inferior : a slight lip on its 
