552 MR. J. PARKIN ON THE 
In the diagram (fig. 7, A), which was taken from a fresh shoot of average 
proportions, seven pairs of secondary flowering shoots are shown, opening 
acropetally. 
The inflorescence, if such a term be allowed for a long, lax, leafy 
flowering shoot, may be regarded as a many-membered pleiochasium with 
dichasial partial inflorescences. The adoption of the climbing habit has, 
as it were, lengthened out the flower-bearing part of the main shoot to what 
we find, e. g., in C. integrifolia. This shoot, however, still ends in a terminal 
primary flower, which is the first to bloom. 
C. Viticella.—This species is a vigorous climber, and the manner in which 
the flowers are borne is somewhat similar to that exhibited by the preceding 
member of the genus, only that the number of pairs of lateral (secondary) 
flowering-shoots produced from a main axis is increased—twelve occurring 
in the specimen from which the diagram (fig. 7, B) was taken. This increase 
in the number of laterals would appear to be correlated with the vigour of 
the elimbing habit, and also to be responsible for the fact that the primary 
flower—the one which terminates the main axis—no longer blooms first. 
Its expansion is deferred till after the lower laterals (secondary flowers) have 
bloomed. In fact, its period of flowering synchronizes with that of the 
middle laterals *. There also appears to be a tendency for the tertiary 
flowers to be suppressed. 
It is, therefore, a short step from such a flower-arrangement as shown by 
Clematis Viticella to one in which, owing to a further increase in the number 
of laterals, the terminal flower is no longer in point of development in 
advance of any of the laterals.. In fact, an ascending order of expansion is 
reached, and provided that the main axis continues growing throughout the 
season, a terminal flower will never be produced. Further, by the complete 
suppression of the tertiary flowers, by the reduction of the leaf-pairs of the 
secondary (lateral) shoots to mere bracts, and at the same time by the 
retention of the foliaceous character of the leaves on the main axis, the 
flowers will become solitary (or in pairs in the case of opposite leaves) and 
axillary. The isolation of the individual flowers is rendered still more 
evident by the long internodes, often a feature of climbing plants. 
Turning to another group of trailing plants, the Convolvu- 
Convolvulus. 
laceæ, which are noted for solitary axillary flowers, an example (Convolvulus 
mauritanicus) has come to the writer’s notice in which an intermediate stage 
in the evolution of the solitary axillary flower according to the above fashion 
may be recognised. . 
The mode of flower-arrangement in Convoleulus mauritanicus (fig. 7, C) 
resembles that in Clematis Viticella, only that the leaves are scattered on the 
stem and not in pairs, as in the latter. "The flowers arise on the main axis 
* Cf. Campanula rapunculoides, p. 542 
