202 
James Small. 
Corolla. The ray florets are shown to be essentially bilabiate 
in development and structure, and the occurrence of inner rows of 
ray florets is shown to be related to the food-supply of the capit- 
ulum. Other results of the investigation of the corolla are the 
elucidation of the evolution of colour in the family from yellow, 
through orange and white, to red, purple, violet and blue, and the 
recognition of the filiform corolla as a reduced type. 
Pappus. The setose pappus is proved to be primitive by its 
mature structure (Chap. V), by the presence of a pulvinus, by its 
development in the individual and in the family, by its common 
occurrence in the earlier known fossil Compositae, and by the 
correlation between pubescence of .the achene and presence of 
pappus (Chap. XII, D). Subsidiary results of the investigation of the 
pappus are a re-affirmation with new evidence of its trichome 
nature, and the elucidation of the evolution of the various types 
from the scabrid setae by fusion and reduction, two tendencies 
which are recognised as general in the other parts of the flower and 
inflorescence of the family. 
Origin of the Capitulum. The development of the capitulum 
is shown to be due to the abortion of the pedicels in a racemose 
umbel rather than the non-elongation of the main axis of a spike. 
All the essential characters of the capitulum are explained by this 
theory. 
Involucre. Two parts are differentiated in the involucre, the 
pericline and the calyculus. The primitive involucre is shown to 
be one with an uniseriate pericline and a slightly developed caly¬ 
culus. This is confirmed by the structure of the earliest known 
fossil involucres. 
Receptacle. The receptacular alveoles and setae are shown to 
be new outgrowths, and the detailed structure and distribution in 
the family of these and other receptacular appendages are 
explained. The paleae of the receptacle are regarded as atavistic 
to a pre-Composite ancestor when they subtend the florets, and 
as a development of the fimbrillate type of appendage where, as in 
the Cynareae, they do not subtend the florets. 
Phyllotaxis, The pericline and calyculus are shown to be 
distinct structures; the pericline is the row of members tran¬ 
sitional between the curve-system of the cauline leaves or calyculus 
and the curve-system of the disc florets. These transitional 
members subtend the ray florets in radiate capitula. The peri¬ 
cline is, therefore, primitively uniseriate. Other results of the 
