230 
H. F. Wernham. 
reflect broad tendencies of biological progress. The advanced 
position of Umbelliflorae relatively to Archichlamydeae has been 
pointed out in chapter II; they stand in the foremost rank of 
advance along all the general evolutionary lines of that series, 
namely, the “ calycifloral ” line, the line of aggregation with zygo- 
morphy of external flowers, and the line of economy in reproductive 
parts. Within both cohorts the progress from a polycarpellary to 
COMPOSITAE 
a bicarpellary gynaecium is observable; in both the ovary is only 
very rarely unilocular; and in both the androecium is primitively 
isomerous with the corolla, and the latter primitively regular. In 
the last-named connections the rubialian tendency of irregularity in 
\ ; 
the corolla coupled with oligomery of the androecium has given rise 
to Valerianaceae and Dipsacaceae; this tendency distinguishes 
Rubiales from Umbelliflorae, where it is non-existent. 
