2 I 8 
H. F. Wernham . 
polyphyletic origin of the Sympetalas ; this aspect will appear in 
the sequel, where the importance of epigyny as a critical character 
—in the delimitation of the larger groups at any rate—will become 
apparent. 
We must first deal in some detail with the groups concerned. 
Particulars of the division into cohorts and families according to 
both the modern systems, together with the significant floral 
characters of each family, are shewn in the accompanying table ; 
the actual order of the families has been altered for the sake of 
convenience in displaying the comparison between the two systems. 
Perhaps the most striking feature of this comparison is the 
essential difference between the two systems in the primary 
allotment of the families into cohorts (natural orders). This 
difference, broadly speaking, is three-fold, having regard to 1st, the 
inclusion of Cucurbitaceae in Engler’s Sympetalae; 2nd, the asso¬ 
ciation of Compositae and Campanulaceae in the same cohort by 
Engler and their separation into different cohorts by Bentham and 
Hooker ; 3rd, the separation of Compositae from the Valerianaceae 
-Dipsacaceae group into different cohorts by Engler, and their 
inclusion in the same cohort by Bentham and Hooker. These 
differences reflect the relative stress laid on different biological 
tendencies by the respective authors, and we shall draw further 
attention to them later. 
Another remarkable feature presented by the table is the great 
discrepancy among the several families in regard to the number of 
species comprised in each. Thus the family Compositae includes 
about 60%, Rubiaceae about 25%, Campanulaceae 5^%, Cucurbitaceae 
4% of the total number of species of Inferae, while the remaining 
5—6% is divided among seven small families. Evolution has ceased, 
if we may so express it, to make experiments on special lines to 
any great extent; its trend among these higher forms is powerful 
and clear, namely, along that line which terminates with the group 
which has been most successful in the struggle for existence, the 
Compositae. 
Beside the relative position of the ovary, the Inferae differ from 
the Bicarpellatae in three significant features :—1st, the androecium 
is, with rare exceptions, isomerous with the corolla. 2nd, in more or 
less intimate connection with this, the tendency to zygomorphy in 
the individual flower is but rarely represented ; regular corollas are 
the general rule, zygomorphy, when it occurs, being usually the pro¬ 
duct of close aggregation of flowers, and appearing in the exterior 
