T H E 
HEW PflYTOIiOGIST. 
Vol. X, Nos. 5 & 6. 
May & June, 1911. 
[Published September 30th] . 
FLORAL EVOLUTION; WITH PARTICULAR REFERENCE 
TO THE SYMPETALOUS DICOTYLEDONS. 
By H. F. Wernham. 
III. The Pentacyclid,e. 
j ^HIS group of Engler’s system corresponds with the Hetero- 
merae of Bentham and Hooker, and, like the latter, includes 
three cohorts—Ericales, Primulales, and Ebenales ; these cohorts 
are identical in the two systems. For convenience of reference, 
the typical characters, especially in so far as the numbers of the 
various parts are concerned, have been summarized in the annexed 
table (see next page), and the relation between the two systems of 
classification has been shewn. 
The Pentacyclidae stand alone among the Sympetalse in the 
character of the androecium. This consists typically of two whorls 
of stamens, the number of members in each whorl equalling the 
number of petals; and, in some cases, the presence of an ancestral 
third whorl may be indicated by the obdiplostemonous arrangement. 
In other cases the stamens are isomerous with the petals, but 
anteposed to them ; not infrequently an outer alternating whorl of 
“ staminodes ” is present. In the Ebenales the androecium is 
frequently polycyclic and the stamens indefinite in number. Only 
rarely are the stamens equal in number to the petals and arranged 
alternately with them. 
The gynaecium is usually either isomerous with the corolla, or 
polycarpellary; only very rarely, in any case, is the ovary 
bicarpellary. 
The corolla, we shall see, retains the polypetalous arrangement 
