MEMOIR ON THE APOCYNACELE. 
PRELIMINARY REMARKS. 
Durine my residence in Brazil, now many years ago, I had numerous opportunities 
for studying many points of structure peculiar to this family, and of examining many 
plants in detail, intending at a future time to describe several Brazilian species. 
This design, however, was superseded by the publication of Dr. Müller's admirable 
monograph in the ‘Flora Brasiliensis, in 1860. But as many curious facts relative to 
the organs of fertilization, and others concerning the structure of the seeds, were 
observed by me, which do not appear to have come under the cognizance of that 
botanist, I have been induced, at this late period, to take up the subject again, and to 
embody my observations in this volume. 
The order, in the time of Jussieu, was little understood, when, in his * Genera’ (1789), 
he comprised in it all Asclepiadaceous plants. The celebrated Robert Brown, in 1811, 
first separated them into two well-characterized distinct families *; this memoir furnished 
the materials for Endlicher’s enumeration of the genera (1838). But we cannot appre- 
ciate too highly the admirable monograph of this interesting family by Prof. A. De 
Candolle, in his * Prodromus’ (1844). We must bear in mind that the task of elaborating 
the features of all the species in full detail was then too vast; and we must regard the 
enumeration of the host of heterogeneous species under the heads of Tabernemontana 
and Echites as an instalment of high value, as it furnished materials for work to be 
afterwards completed. Dr. Müller followed this example, in describing under the same 
heads a mass of Brazilian species ; but he did little to enable us to distinguish one species 
from another. : 
In order to promote this object, it appears to me necessary to classify and subdivide 
the whole of them into uniform groups, each marked by peculiar and easily recognized 
characters. In aid of this design the present memoir is offered; but it is limited in its 
range. 
* Mem. Wern. Soc. i. p. 12. 
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