Origin and Development of the Composites. 15 
bilabiate corolla showed a development intermediate between that 
of the ordinary ray corolla and that of the tubular corolla. 
Coulter (20) considered that the primordia of all four sets of 
floral organs are blended at first and that the late appearance of the 
calyx is due only to the late development of its upper portion. 
Martin (51) agrees with Coulter and points out that of necessity the 
“ calyx-tube ” must he the first part to appear. As no demarcation 
can he observed between the ovary wall and the so-called calyx-tube 
it would seem more in accordance with modern nomenclature to 
describe the undifferentiated primordium as the receptacle of the 
flower. 
The most recent contributions are those by Merrell on Silphium 
(54) and by the writer on Senecio, Calendula and Taraxacum (81). 
Merrell again confirms the corolla as the first floral part to he 
differentiated and goes into many interesting details of the other 
parts of the floret. 
Colour. Hildebrand in his elaborate treatise (37) includes a 
number of observations on the Compositae. He established the 
colour sequence—green, yellow, white, red, violet, blue—by 
observing the following facts—blue flowers vary to violet, red and 
white vary but seldom to yellow; red flowers vary more to yellow 
than do blue flowers; yellows may vary to blue but more often to 
red ; green flowers give yellow and white flowers ; yellow gives 
orange with red plastids and the colour of the sap gives reds and 
blues. 
Muller’s contributions are extensive but he gives two very 
useful historical accounts (60-61). The views expressed in one of 
Blue 
