2 ANNALS OF THE ROYAL BOTANIC GARDEN, CALCUTTA. 
And it is only for the isolated worker in the bookless waste of an Indian station - forest 
camp that I venture here to offer a few remarks on the organography of ties ae y- | 
The calyx consists of a single whorl of three sepals which may either be free or more 
or less completely united. The freedom or union of the sepals is, however, a character SO 
inconstant in its co-ordination with special characters in other organs, that it can be 
relied upon only for the separation of species. The sepals may have either imbricate or 
valvate sestivation; or in the bud they may not touch at all. The sepaline xestivation, 
however, varies so much in flowers which are similar in other respects that it also fails to 
afford characters of far-reaching significance. The six petals of the corolla are arranged 
in two whorls, but to this there are some exceptions: for im the genus Enantia the outer 
whorl is absent; while in some species of Unona, Anona and Rollinia, and in the 
African genus Clathrospermum, the inner whorl is either greatly reduced in size or 1s 
altogether suppressed. Eupomatia differs from all other members of the family by having 
neither calyx nor corolla. All the petals are, in the majority of species of the family, larger 
than the sepals. And, of the two corolline whorls, the petals of the outer are usually the 
larger. In some cases (¢g., in certain species of Sagerwa, Popowia and Artabotrys) the two 
rows are of equal size; while in a species of Uvaria to which generic rank* was given by 
Zollinger, and notably in Miliusa and Pheanthus, the petals of the inner whorl are much 
larger than those of the outer. The estivation of the corolla resembies that of the calyx, 
but is much more constant. It is therefore of more use in affording characters to the 
systematic botanist. For example, the large tribes Unonee and Uvariee are practically 
separated by the nature of the petaline estivation—the former having valvate and the 
latter imbricate petals. Absolute uniformity between the two corolline whorls in the 
matter of eestivation does not, however, obtain: for in some species of Uvaria that of the 
outer whorl is imbricate, while that of the inner is valvate. 
As regards shape, considerable differences obtain amongst the petals of the family ; 
there being numerous gradations from rotund to ovate, obovate and oblong; from lanceolate 
to lmear and even to triquetrous or cylindric; while, in a few species, those of the inner 
row are spathulate with long filiform claws. Considerable modifications also occur in the 
bases of the petals, especially in those of the inner row. In some cases the bases are 
merely hollowed out so as partially to embrace and cover the andro-gyncecium ; while in 
others there are distinctly saccate expansions of the bases of the petals by the union of 
which by their edges the whole of the andro-gynecium is entirely covered. In some 
genera, (¢.g., ollina) the petals have dorsal processes. As these diversities in the 
petals are usually co-related to certain diversities in other organs, they haye important 
uses in classification: and, as a matter of fact, they afford the characters on which 
the late Mr. Bentham and Sir Joseph Hooker founded their division of the whole order 
into tribes; while, in M. Baillon’s classification, they form the basis of the subdivi- 
‘sions of the series Anonew to which he relegates the bulk of the order. Although in 
the majority of the species the petals are free from each other, there are numerous 
exceptions in which the. members of the same whorl are united by their edges either 
at the bases when the latter are saccate, or throughout their whole length. There are 
also the less frequent cases (¢.9., Monodera) where the petals of both whorls are united 
into a short common tube. Characters of far-reaching significance to the systematist are 
not, however, obtainable from either the partial or entire union of petals; and this on 
* Anomianthus, Zoll. 
