EVOLUTION OF THE INFLORESCENCE. 521 
in the production of a single flower of many parts. An injury to this flower 
may result in the total loss of seed production by this shoot., On the other 
hand, if it utilises this material in the formation of several flowers of fewer 
parts each, blooming successively as is the manner of inflorescences, the 
chances of an injury destroying the whole reproductive capacity of the shoot 
are minimised, as some of the flowers may escape and so set seed. The 
capability of the floral part of a shoot to branch, thus producing lateral 
flowers in addition to the terminal one, gives the plant an advantage, It 
lessens its risks. 
The above remarks may not apply to intercalary inflorescences. The 
bunching together of flowers in this type of grouping may, on the contrary, 
have been evolved to render the flowers more evident to insects or to 
facilitate their visits. This is suggested by the fact that the intercalary 
inflorescence seems to have arisen, not so much from the splitting up as it 
were of one flower into several, but rather from the massing together of a 
number of solitary flowers through the suppression of the intervening 
foliage and the shortening of the internodes. 
IV. THE SOLITARY TERMINAL FLOWER, AND THE ORIGIN FROM IT OF 
THE SIMPLEST INFLORESCENCE—THE DICHASIUM. 
On general grounds it is reasonable to assume that flowers were originally 
borne in a solitary fashion, and that the clustering of them together without 
intervening foliage is a later development. Further, it would appear more 
likely that such solitary flowers were borne terminally to leafy shoots, rather 
than produced in an axillary manner. Assuming, then, that this is the 
primitive way in which flowers were borne, the question may be asked, 
Do plants still exist exhibiting this early mode of flower-bearing ? Solitary 
terminal flowers are not uncommon, but we must be on our guard in assuming 
primitiveness in every case. Some may have arisen through the reduction 
of an inflorescence to a single flower. Each must be judged on its own 
merits. However, as will be shown later, the most conspicuous examples of 
solitary terminal flowers occur in those families—e. g., the Magnoliacez, 
Ranunculacee, ete.—which on other grounds are now generally regarded as 
primitive. Reduction seems extremely unlikely here; at any rate, no 
evidence has been shown for it. 
At this stage of the paper it may not be without interest to compare briefly 
the manner in which the * flowers" (strobili) are borne in the Gymnosperms, 
both recent and extinct. In doing so, we may leave on one side the study of 
the Cordaitean-Coniferous group, as it is but remotely connected with the 
Angiospermous line of descent, and confine ourselves to the Bennittitean- 
- Cyeadalean plexus, from which it is now generally assumed that the Angio- 
sperms have sprung. 
