BIXACEÆ. 303 
orthotropous or incompletely anatropous ovules, and by their non- 
fornicate seeds! They are very nearly allied also to what we 
consider Z/wrnereæ, having the same corolla and mode of placen- 
tation, and are only separated by the mode of insertion of the 
corolla. Violacee having regular flowers, among which Zetrathylacium 
has been placed, and including the very nearly allied genus Leonia, 
are only distinguished from the Pivaceæ with  oligandrous 
flowers, by the insertion of the stamens in the perigynous types, or 
by the arrangement of the pieces of the androceum in the types 
with hypogynous insertion.” The Passifloracee, to which Ryania 
has been attached, is distinguished from Bivacee by the presence 
of the crown of appendages accompanying the perianth, and it is on 
this account that we have separated from it the Papayee, which 
have not this character, and which Linp1zy has shown to have a 
great affinity with Pangiee. 
Some Capparidacee analogous to Bivacee are distinctly separated 
from it by their exalbuminous seeds. We have already remarked* 
the affinity of Bivaceæ with certain groups having usually distinct 
carpels, and, moreover, very analogous by the rest of their organiza- 
tion. The species of Oncoda, principally those of the section Mayna, 
seem to represent the parietal mode of placentation of Maynoliacee, to 
which they have sometimes been ascribed. Camella, and Zrythros- 
permum have been placed close beside the Bivacee, or even among them, 
because this differential character in the placentation no longer 
exists among them. To distinguish them, they have only the charac- 
ters drawn from the organization of the perianth and androceum. 
Cochlospermum and Turneree seem to be forms of the parietal 
placentation of Wormia and Acrotrema, and by the union of their 
carpels, to be to the latter what the Cis/aceæ is to Hibbertiee, Mono- 
doreæ to Anonaceæ, Papaveracee to Ranunculaceae, Nympheeæ (Water 
lilies) to Nelwmbee and Cabombeæ, and Berberidopsis to the other 
Berberidacee. 
The number of useful species‘ is considerable, and their properties 

1 See Adansonia, x. 258. 3 See Hist. des Plantes, i. 123. 
2 & Violarieæ cet. vald. affin. differ, a Bixi- 4 Enpt., “Enchirid., 477, 479.—Linv1.., Veg. 
neis oligandris antheris circa ovar. connivent.  Kingd., 328, 331; Fv. Med. 101, 111. — 
connatisve.” (B. H., Gen., 122.) RosENTH., Syn, Pl. Diaphor., 662, 1143. 
