76 ILLUSTRATIONS OF 
and one that will probably be found to constitute an unerring 
line of distinction between the Solanacee and Scrophu- 
larinee, orders so closely allied, that our most able 
Botanists are yet often undecided as to which of the two, 
certain plants ought to be referred. This is a desideratum 
of some moment, and one that appears to me worthy 
of being pursued: it seems to me possible to reconcile 
all the discrepancies that at first view stand in the way 
of such a line of demarcation: indeed, there exist many 
singular analogies between some plants of the Salpiglossidee, 
and other Scrophularineous genera, and some of tribes of 
the Solanacee as above defined, which will probably assist 
us in this inquiry, but I will reserve to a future opportunity 
the exposition of my sentiments on this subject, in order 
to have more ample means of examining the characters of 
these plants, and of availing myself of the assistance that 
will be afforded by the extensive views, and vast collection of 
facts, made by the learned author of the monograph of 
the Scrophularinee, in the forthcoming volume of the Pro- 
dromus. 
SESsEA. 
In order to confirm what I have before stated respecting 
the affinities of Metternichia, 1 will offer a few observations 
upon the genus Sessea of Ruiz and Pavon, two species 
of which are only recorded, both being well figured by 
the authors of the Flora Peruviana; but as I have also 
had an opportunity of examining two other undescribed 
species existing in the splendid herbarium of Sir William 
Hooker, and as the characters of the seed have not been 
yet sufficiently well determined, I venture to propose here 
an amended definition of the genus and a description of 
the four species. 
Sessea, R.& P. (Char, emend.)—Calyx tubulosus, 5-den- 
tatus. Corolla hypogyna, infundibuliformi-tubulosa, limbi 
5-fidi erecto-patenti laciniis ovatis, estivatione condu- 
plicatis. Stamina 5, tubi medio corolle inserta, inclusa ; 
