48 
CONTRIBUTIONS TO BOTANY. 
a report of my observations upon the several genera of the Ola- 
cncem, Santalacea, Aquifoliacea, Loranthacem, Styracea, &c., will 
consequently be offered in succession, and the results of these 
researches will at the same time be demonstrated by analytieal 
drawings. 
Observations on the Affinities of the Icacinace^. 
One of the foremost of the conclusions last alluded to, is the 
necessity of removing the tribe of the Icacinece of Mr. Bentham 
from the family of the Olacacece, for which many cogent reasons 
have already been offered [huj. op. p. 33), and this group I 
])ropose to establish at once as suggested, either as a suborder, or 
more deservedly as a distinct family under the name above 
■stated. In his excellent memoir on the Olacinece before quoted, 
]Mr. Bentham enumerated only eleven genera of that order, two 
of which were then first described by him. Of these five belonged 
to his tribe of the Icacmece, and one I have shown has no rela- 
tion there; hence only five genera out of that list were then 
known as really appertaining to the former family. I have now 
enumerated thirteen genera of the Olacacea [ante, p. 32), 
and an equal number of the Icacinacea [idem, p. 34) *. This last- 
mentioned group exhibits characters so widely diflFerent from 
those of the former, that it becomes necessary to place the two 
at a considerable distance in the system. These characters con- 
sist in their frequently polygamous, almost dioecious flowers ; the 
alternate position of their stamens with respect to the petals ; 
the evidently normal polycarpellary structure of the ovarium (for 
where developed with more than one cell, the dissepiments are 
always found complete at their summit) ; the pendulous position 
of their ovules, generally two in each cell, near the summit, 
where they are suspended, one always more or less above the 
other, from a peculiar cupshaped podosperm ; their constantly 
indutive seeds ; the existence of a distinct testa, of inner integu- 
ments, of a chalaza _and of a raphe : all these are important dif- 
ferences, quite at variance with the very peculiar points of struc- 
ture that characterize the Olacacece. 
With such completely ir recon cileable characters, there is only 
one proper course to pursue, and that is to separate them ; but 
it then remains to be considered, where in such case they should 
be placed in the system, for it is evident that they cannot even 
remain in juxtaposition. In the face of the difficulty of com- 
* One of these, Ptychopetalum, was placed here, because its ovules were 
stated to be attached to a parietal placenta ; but having since had an oppor- 
tunity of examining it, I find it to possess the general characters of the 
Olacacece. 
