and Affinities of Trapella . 107 
Pedalium on the one side, and Trapella on the other ; this is 
seen especially in the form of the leaves and in the general 
habit ; it must however be remembered that Pretrea is 
adapted to an arid climate. The greatest difference is shown 
by the fruit, which is primarily bilocular with erect basal 
ovules ; partitions are developed as outgrowths from the 
median wall, which, becoming forked before meeting the 
dorsal and ventral walls of the fruit, divide each loculus into 
three compartments. The compartments lying right and left 
respectively are fertile, but the median compartment of each 
loculus is empty. 
The genera included in the tribe of the Sesameae are to be 
derived from the Pedalieae through the genus Harpagophytum . 
Baillon 1 has pointed out that in H Grandidieri dorsal and 
ventral ingrowths arise, which do not reach the placenta at 
any stage. This I can confirm for the species in question, and 
find that Decaisne 2 figured it for H. Zeyheri . In the recently 
created genus, Holubia , Oliv. 3 , which is placed in the tribe 
Pedalieae , it seems that there is also a tendency to dorsal and 
ventral ingrowths of the ovary wall ; these, however, do not 
reach the placenta. Doubtless Holubia is nearly allied to 
Harpagophytum , though its fruit is as yet unknown. It may 
be a link between Pedalium and Harpagophytum . In this 
way the completely divided loculi of Sesamum and Roger ia 
are foreshadowed, as indicated by Baillon (loc. cit). It is 
only necessary to conceive the false septa of Harpagophytum 
fusing completely with the axile placenta to give us the four 
locelli, each bearing numerous ovules along its inner angle, of 
Sesamum and its allies. In Rogeria , it should be mentioned, 
the two anterior compartments are much larger than the 
posterior, the latter containing only a few, sometimes no 
seeds. 
1 H. Baillon, Notes sur les Pedalinees in Bulletin mensuel de la Soc. Linn, de 
Paris, No. 84 (1887), p. 665. 
2 Decaisne, Revue du groupe des Pedalinees, pi. ii. fig. 6, in Annales d. Sc. Nat. 
Bot. 5 ser. T. iii. 
3 D. Oliver, in Hook. Ic. PI. tab. 1475. 
