BOTANICAL INFORMATION. 231 
by their milky juice, their regular isomerous flowers, the 
contorted or valvate æstivation of the corolla, the bicarpel- 
lary pluriovulate ovarium, with a placentation never truly 
axile, besides the opposite exstipulate leaves, the ovaries 
distinct at the base of the style, with the styles joined at the 
apex, the follicular or baccate fruit, and several other cha- 
racters which, though not without exception, are so prevalent 
in the two orders as generally to enable the botanist to recog- 
nise them at first sight. ‘They are separated from each other 
on account of the singular structure of the stamens in Ascle- 
piadacee which does not exist in Apocynacee ; moreover, the 
corolla is generally valvate in the former, always contorted 
in the latter. 
The Apocynacee, by Alphonse de Candolle, contain ninety- 
four genera (besides two doubtful ones) of which twenty-three 
are here first established. "The generic characters are given 
With accuracy and detail, and are taken chiefly from those 
organs, whether reproductive or vegetative, which have ap- 
peared in each case the most constant, without so much 
reference to preconceived notions of the absolute importance 
of certain modifications as is too frequently the case; the 
characters have moreover been carefully verified in all the 
species of which the author possessed specimens, and the 
general principles which guided him are fully explained in a 
memoir published in the first vol. of the third series of the 
Annales des Sciences Naturelles. We have thus a complete 
concise and satisfactory monograph of the order brought down 
to the commencement of 1844, and singularly facilitating the 
determination of its species. H 
The principal division of the order is taken from the degree 
of coalition of the ovaries, and the presence and situation, or 
absence, of a coma or tuft to the seed ; the latter character has 
the inconyenience of being observable only in the ripe fruit 
which is seldom to be seen in herbaria, but M. de Can- 
dolle has satisfactorily shown in his memoir, that it is the 
best which has yet been proposed. He there gives the fol- 
