io6 Oliver . — On the Structure , Development , 
An examination of the chief genera 1 soon showed me that 
those forms with bilocular ovary and axile placentation, in 
which the loculi do not become subdivided by the development 
of false septa stretching across, must be regarded as typical of 
the Order — as in Bentham and Hooker’s group Pedalieae. 
Others with ovaries unilocular and plurilocular to be regarded 
respectively as distinct forms with different origin, and as 
forms derived from such as have the typical bilocular arrange- 
ment, as will appear in the sequel. 
In Pedalium and Pterodiscus the ovary is bilocular, with 
two pendulous ovules in each loculus attached to the septum 
right and left of the median line as in Trapella . In Harpago- 
phytum, which is placed in the same group, we find the same 
characters, combined with numerous ovules. Our plant I 
believe comes nearest to Pedalium , differing in its aquatic 
habit and semi-inferior ovary. If this surmise be correct, 
Trapella must have diverged early — whilst yet its ovary was 
superior and both loculi were fully developed. This state of 
things has persisted in Pedalium , but in Trapella , for reasons 
to be considered hereafter, the ovary has become adherent and 
the anterior loculus rudimentary. 
The tribe Pretreeae have also probably diverged from the 
same centre, and Pretrea shows a strong resemblance to 
under Gesneraceae) a tribe of Scrophulariaceae — Sesameae, under which the genera 
are given without any further subdivision of the tribe. The only reference to 
Trapella is in a foot-note, where it is spoken of as a genus of doubtful affinity. In 
this place, with the results of an investigation of complete material before me, I try 
to show its close relationship to Pedalium. Baillon had only the incomplete account 
(Hook. Ic. PI. 1595), made from the first specimens which arrived, to go by. 
1 For convenience, the arrangement of the genera adopted by Bentham and 
Hooker in the Genera Plantarum is given here. 
Tribe I. — Martynieae. 
1. Martynia. 
2. Craniolaria. 
Tribe II. — Pedalieae. 
3. Pedalium. 
4. Pterodiscus. 
5. Harpagophytum. 
Tribe III. — Sesameae. 
6. Rogeria. 
7. Sesamothamnus. 
8. Sesamum. 
9. Ceratotheca. 
Tribe IV.— -Pretreeae. 
10. Pretrea. 
1 1 . Linariopsis. 
12. Josephinia. 
