SOUTH AMERICAN PLANTS. 123 
on account of the gynobasic insertion of the carpels, but 
the transition is now more distinctly visible and gradual, 
through the medium of the Hhretiacea, this new group, and the 
Nolanacee. 
This affinity of Sclerophylar (having suspended ovules) with 
the Nolanacee and Borraginee, (having gynobasic carpels and 
erect ovules,) it must be confessed, does not, at first sight, appear 
so evident as will be seen on further enquiry. In this con- 
sideration, one feature should be constantly borne in mind, I 
mean that of the relative position and mode of attachment of the 
ovules: in most cases analogous to the present one, (i. e. where 
the radicle of the embryo points towards the hilum,) these may 
vary either in having a superior pomt of suspension, an axile 
attachment, or a basic origin,—differences that really amount to 
little else than the relative height of the poimt of adhesion of the 
carpels, or that terminal summit of the gynobase, where its 
nourishing vessels, proceeding from the torus, penetrate the walls 
of the ovaria, and which can always be distinguished from the 
fertilizing vessels proceeding from the style. These several con- 
ditions. have been ably explained by M. Aug. de St. Hilaire, in 
his admirable paper on the gynobase (Mem. Mus. 10, p. 131.) 
Following up this view of the case, there will not be found so 
great an amount of discrepancy in the structure of the seed of 
Sclerophylax, and that of the various genera included in the 
orders above mentioned ; for, in examining the dissepiment of the 
seed of this genus, the gynobasic vessels (as might be expected) 
are seen as a distinct rachis along its central axis, terminating in 
_ the point of suspension of the ovules, and presenting an instance 
somewhat analogous to that which St. Hilaire calls an elevated 
~ gynobase. In Nolanacee and Borraginacea, where generally there 
exists, on the contrary, a very depressed gynobase, it is the style 
that is seen in an analogous position, as a rachis in the central 
axis of the carpels, in consequence of the ovaries having an en- 
tirely basic attachment : in these two extreme cases, the embryo 
is alike seen in the axis of the albuminous seed, with the radicle 
directed to the point of its attachment. Even in the Order Bor- 
R2 
