9998 MR. J. PARKIN ON THE 
each terminates in a flower and bears a pair of bracteoles, which may have 
buds in their axils, thus showing a tendeney to branch further. 
Rosa indica is an example of a more branched inflorescence, leading to the 
many flowered, copiously branched, somewhat compact clusters to be found 
in A. sempervirens, R. multiflora, ete. 
Pyrus.—This is the last genus to be taken for the purpose of illustrating 
the origin of an inflorescence from the solitary terminal flower, 
Pyrus Cydonia (the Quince) and P. germanica (the Medlar) supply 
instances of species with solitary terminal flowers. There are no reduced 
leaf-structures below the flower, the leaves remaining foliaceous right up to 
the flower-stalk. 
From such species with solitary flowers, we can pass through ones like 
P. japonica and P. Malus with few-flowered unbranched cymes to forms 
like P. Aueuparia with many-flowered, branched cymose inflorescences, 
V. Tug EVOLUTION or RACEMOSE INFLORESCENCES FROM THE 
PLEIOCHASIUM OR PANICLE. 
In the preceding seetion of this paper it has been shown that the earliest 
form of flower-cluster is the di- (or tri-)chasium, a very simple eymose 
inflorescence, consisting of the terminal flower, which is the first to bloom, 
and of two (or three) lateral flowers. These latter terminate secondary axes 
which are borne in the axils of leaves (either foliar or bract-like in form), 
situated on the main axis just below the terminal flower. These secondary 
floral shoots bear, as a rule, a pair of reduced leaf-structures (bracteoles), 
which often produce in their axils tertiary flower-buds. 
One common way of advancement from the above simple cluster consists 
in augmenting the number of secondary floral axes beyond three. — The 
inflorescence then becomes a pleiochasium or multiparous cyme, with di- 
chasial subordinate branching, as each secondary floral shoot usually branches 
,80, producing tertiary flowers to some extent. Inflorescences of this type, 
‘when of a lax habit (long internodes), have often had applied to them the 
(term panicle. In the genus Helleborus already. studied (p. 533), Z. Jætidus 
affords an example of a species with a panicle of this nature. Though it 
is many-flowered, yet the terminal flower of its main axis is the first to 
bloom. This genus does not allow us to continue further the study of the 
inflorescence along this line, as this is the furthest advancement. to which 
apparently the genus has attained. 
Two other genera, however, viz. Delphinium and Aconitum of the same 
family, the Ranunculaceæ, afford some scope for tracing the manner of 
transition from the cymose to the racemose type of inflorescence. It is 
interesting to note here that these two genera not only have the most evolved 
inflorescences in the family, but also the highest, most specialised, flowers. 
