certain Species of the Genus Christisonia. 1 3 1 
The ovary is bilocular in its lower region and unilocular 
above; in the latter case the placentation is parietal. In this 
plant the basal portions of the two bipartite placentas very 
nearly meet in the centre. In the lower, bilocular part of the 
ovary, where the projections have become united to form 
a dividing wall, the placentation is axile, two placentas, 
bearing a large number of minute ovules, projecting into 
each cavity. 
Comparison of the Forms. 
Of the three species belonging to this genus which, in the 
foregoing pages, have been described, two, viz., C. bicolor , 
Gardn., and C. s?ibacaulis , Gardn., are closely allied, while 
the third, C. neilgherrica, Gardn., presents various characters 
which render it quite distinct from either of the preceding, 
insomuch that it has been placed by some authors in the 
separate genus Campbellia h 
I will first discuss the relations between the first two species 
described. It will have been gathered from the description 
that C. bicolor , Gardn., is much more typical and normal in all 
parts of its structure than is C. S7ibacaulis, Gardn. This is 
seen, first, in the structure of the root, where the typical 
radial arrangement of the central cylinder and the presence 
of a distinct endodermal layer present a marked contrast to 
what we find in C. subacaulis , Gardn., where, owing to the 
greater reduction of the xylem and the abnormal development 
of the phloem, the radial arrangement of the cylinder has 
become completely obscured, while no endodermal layer can 
be distinguished on the outside. The latter species is further 
distinguished by the complete absence of any local mucilaginous 
thickenings of the cell-wall, which is so conspicuous a feature 
in the cortical cells of the root of C. bicolor, Gardn. 
In connexion with the more reduced form and structure of 
C. subacaulis , Gardn., we find the haustorial part of the root- 
system very strongly developed ; in consequence of its para- 
1 Wight, loc. cit. 
K 2 
