EVOLUTION OF THE INFLORESCENCE. 539 
The main points noted in the passage from eymose to racemose inflor- 
escences in these genera are as follows :— 
The number of lateral floral shoots increase, so that the main terminal 
flower no longer blooms first. The flowers then tend to open in acropetalous 
succession from the commencement. The next step comes about through the 
flower-buds of the uppermost part of the inflorescence never expanding; this 
part, in faet, becomes arrested in its development and finally aborts, leaving a 
mere filament or protuberance in its place. In this way the original terminal 
flower disappears. The inflorescence is now racemose. 
Below, a few details are given regarding species exemplifying the above 
points. A more extended study of these two genera would probably reveal 
a greater number of examples of inflorescences between the pleiochasium 
and the true raceme or spike. 
Delphinium eashmerianum has a quite lax, somewhat foliaceous, few-flowered 
inflorescence (a pleiochasium, in fact, with four secondary floral axes), the 
terminal flower of which is the first to bloom, the lateral flowers opening 
somewhat basipetally. 
D. yunnanense and garden forms of perennial Larkspurs have racemose 
inflorescences, the aborted upper parts being merely represented by minute 
filaments or slight protuberances. 
D. Consolida.—Vhe inflorescence of this annual might seem at first sight 
to have a terminal flower, but the uppermost bloom is really lateral, pro- 
ceeding from the axil of a bract and bearing on its pedicel the usual pair of 
bracteoles. The real apex of the inflorescence is almost obliterated, no 
filament or even protuberance oceurring. 
Aconitum anthorvideum has a raceme-like inflorescence with a terminal 
flower. 
A. Anthora var. racemosa.--The uppermost part of the inflorescence is 
arrested in its growth, so no terminal flower expands. 
A. Napellus and A. Lyeoctonum.—The racemose spikes end in terminal 
filaments, which are the vestigial remains of the aborted uppermost parts of 
the inflorescences. . 
A. variegatum has a lax inflorescence, but no terminal flower, the axis 
ending in an elbow or slight protuberance. The individual flowers, how- 
ever, do not open in a strictly acropetalous order, some of the upper ones 
expanding before the lower ones. 
PAPAVERACES. 
As in the Ranuneulacez, the genera with the most specialised flowers 
have also advanced inflorescences. The Fumarioides (sometimes recognised 
as a separate family, the Fumariacese) illustrate the passage from cymose to 
racemose inflorescences. 
