EVOLUTION OF THE INFLORESCENCE. 549 
two types of solitary flower, either in the direction of deriving the one from 
the other, or in deciding which mode of arrangement is the more primitive. 
The two have been kept apart in descriptive morphology, even more so than 
have the two main types of inflorescence, the cymose and racemose. 
The solitary axillary flower was a puzzle to the writer for some time after 
the connection between cymose and racemose inflorescences became clear. 
On general grounds it would appear hardly likely that there is no evolu- 
tionary connection between the two, and if the one has come from the other, 
then the derivation of the axillary from the terminal flower would seem 
more likely than the other alternative. 
From a fairly extensive comparison of species bearing solitary axillary 
flowers with those related forms having their flowers arranged otherwise, 
three different kinds of solitary axillary flowers have been made out, all 
capable of derivation either directly or indirectly from the solitary terminal 
flower. 
(1) Type of solitary axillary flower occurring in arborescent plants, capable oj 
being directly derived from the solitary terminal flower. 
Examples of this type occur in the genera Michelia and ZHlicium, belonging 
to the Magnoliacew, a family already pointed out as containing for the most 
part primitive solitary terminal flowers. To find axillary flowers in such 
a family seems strange at first, but a comparative study shows how these 
seemingly opposed modes of flower-bearing are closely connected. 
In Angiosperms it may be held that, primitively, the main (plumular) 
axis produced first a succession of foliage leaves, and after sufficient energy 
had been stored, these gave place to reproductive leaves (sporophylls), that is 
to say, to a terminal solitary flower. Examples have already been given of 
species with plumular axes ending each in a flower. Owing to the production 
of a flower, the vegetative growth in length of the main axis is brought to 
a close, and new foliage is obtained by the pushing out of lateral shoots. 
These likewise, after growing vegetatively for some time, may end each in 
a flower. In a primitive form we may consider these secondary shoots 
blooming after the primary. 
In trees it might be a disadvantage to cut short the vegetative growth of 
the main axis by flower-production, and at the same time it might be 
desirable not to delay seed-formation. Hence the lateral (lower) shoots 
might commence flowering earlier than the main (upper) shoots. There 
does seem such a tendency in many trees and shrubs to transfer, as it were, 
flower-bearing from the main (upper) shoots to the secondary (lower) ones, 
e. g., Magnolia grandiflora, Calycanthus, Rosa spp. The tree or shrub can 
thus continue its upward vegetative growth without at the same time 
deferring its flowering. 
