382 
H. F. Wernham. 
we have seen, plays an important part among the descendants of 
the Calycifloral Plexus. 
Within the Transitional Group an active fundamental differ¬ 
entiating tendency is reflected, namely, the progressive specialization 
of the fruit; this is exemplified particularly in Nolanacese and 
Boraginaceae. The key-note of this specialization is “schizocarpy ” 
—the association of a fruit-body with each separate seed, thereby 
extending the period of seed-protection without prejudicing seed- 
dispersal. This tendency, involving of necessity a considerable 
reduction in ovule-number, led to the section Diovulat/E of the 
Higher Tubiflorae—the Lamiales of Bentham and Hooker. 
Those Tubiflorae of the Transitional Group which escaped the 
tendency to schizocarpy retained an indefinite number of ovules in 
the ovary and led, in virtue of the acquisition of Individual Zygo- 
morphy and consequent abortion of one or more of the stamens, 
to the Multiovulat,®— the Personales of Bentham and Hooker. 
From the Calycifloral Plexus of Archichlamydeae three distinct 
lines diverge. Two lead directly to sympetalous groups (Cucurbi- 
tales 1 and the Campanal Stock), and the third indirectly (Umbelli- 
floral and Rubialian Stocks). Of these the cucurbitaceous branch 
is to be regarded as quite short, in view of the close connection 
between Cucurbitaceae and Parietales (Passiflorales). 
Of the other two lines, the Campanal arose before the tendency 
to epigyny was fully realized, determined principally by the Pollen- 
Presentation tendency. The subsequent course of descent from the 
Campanal Stock (Campanulatte) is determined in the main by that 
aggregation-tendency which produced Compositae, with its con¬ 
comitant zygomorphy and reduction of megasporangia to one per 
floret. The side-shoot bearing Campanulaceae and Goodeniaceae 
appears at an early stage, determined by Individual Zygomorphy 
and progressive elaboration of the pollen-presentation mechanism. 
The third line of Inferae originated from the tendency to what 
we have called the “ umbellifloral ” arrangement of the flowers, in 
which the inflorescence is fundamentally cymose, and the flowers 
tend to lie in a continuous more or less expanded surface. This 
1 A separate cohort (natural order) coterminous with the family 
Cucurbitaceae. We conclude from our remarks on this group 
in the preceding chapter that its isolated position, relatively 
to the rest of the Sympetalae, seems to warrant this rank. 
If, however, Cucurbitaceae be retained among “ Polypetalae,” 
it may reasonably be included in the same cohort with 
Passifloraceie, as in the system of Bentham and Hooker ; and 
this latter most probably represents their true position in a 
natural scheme. 
