122 BOTANY OF CONGO. 



and superum occur ; and in one genus of wliicli, namely, 

 BJachcellia, the segments of the perianthium, though the 

 complete number, in relation to the other genera of the 

 order, be present, are all of similar texture and form, and are 

 disposed nearly in a simple series. If the approximation 

 of these three families be admitted, they may be considered 

 as forming a class intermediate between Polypetalse and 

 Apetalse, whose principal characters would consist in the 

 segments of the calyx being disposed in a double series, 

 and in the absence of petals ; -the different orders nearly 

 agreeing with each other in the structure of their seeds, 

 and to a considerable degree in that of the ovarium. 



The formation of this class, however, connected on the 

 440] one hand with Apetalae by Samydeas,^ and on the other, 

 though as it seems to me less intimately, with Polypetalae 

 by Violeae, would not accord with any arrangement of 

 natural orders that has yet been given. While the admis- 

 sion of the floral envelope being entirely calyx ; and of the 

 affinity of the class with Violese, would certainly be un- 

 favorable to M. de CandoUe's ingenious hypothesis of 

 petals in all cases being modified stamina. 



VIOLE^.^ This order does not appear to me so 

 nearly related to Passifloreee as M. du Petit Thouars is dis- 

 posed to consider it ; for it not only has a genuine poly- 

 petalous corolla, which is hypogynous, but its antlierse 

 differ materially in structure, and its simple calyx is divided 

 to the base. The irregularity both of petals and stamina 

 in the original genera of the order, namely, Viola, Pom- 

 balia,^ and Hybanthus, though characters of considerable 

 importance, are not in all cases connected with such a 

 difference in habit as to prevent their union with certain 

 regular flowered genera, which it has lately been proposed 

 to associate with them. 



The collection from Congo contains two plants belonging 

 to the section of Violese with regular flowers. One of 



^ Ventenat in Mem. de Vlnstit. Sc. Thjs. 1807, 2 sent. -p. 142. 



2 Juss. Gen. PL 295. Ventenat Malmcns, 27. 



^ Vandelli Fasc. PL p. 7, t. 1. loiiidium, Venten, Malmais. 27. 



