no Oliver . — On the Structure , Development , 
other genera would probably be found not really entirely 
‘ exalbuminous ’ 1 . 
Hence, then, although at first sight the gap between Trapella 
and Pedalium appears a wide one, still when we consider that 
Trapella has entirely changed its habit of life and lived under 
fresh conditions, it is not difficult to understand that the 
relationship may be a close one, though the differences be 
considerable. 
The alternatives to placing Trapella in Pedalineae would be 
to place it in Myoporineae, or to make it the type of a new 
Natural Order. Such a course as that of founding a new 
Natural Order would be, in the present state of bilabiate 
Monopetalae, ill-advised 2 . 
Trapella must thus rest in Pedalineae, forming the only 
genus in a new tribe, Trapelleae. Following the ‘ Genera 
Plantarum’ classification, this will make five tribes in all. (See 
footnote, supra, p. 10 61 ) 
Though coming in touch with Myoporineae in the form and 
arrangement of the seeds, it is separated therefrom by its 
eminently Pedalinaceous fruit and opposite leaves. None the 
less Trapella forms a connecting link between the two, some- 
what artificially separated, cohorts of the Genera Plantarum, 
namely the Personales and the Lamiales ; Pedalineae being 
placed with the former, Myoporineae with the latter. 
In conclusion, I wish to express my indebtedness to my 
father, at whose suggestion this work* was undertaken, and to 
Mr. Thiselton Dyer, for his warm interest, and for the many 
facilities which he has afforded me. 
Miss Matilda Smith has kindly drawn for me figures 1-7 on 
Plate V. 
1 This I find to be the case in Plerodzscus, Rogeria and Linariopsis , in addition 
to Pedalium . 
2 The arguments against investing an aberrant monotypic genus with the dignity 
of a separate Natural Order have been very succinctly stated by Sir Joseph Hooker, 
in his paper on Hydrothrix , a new genus of Pontederiaceae, in this Journal, vol. i. 
pp. 91-2. 
Jodrell Laboratory, Kew, 
March , 1888. 
