TRANSACTIONS OF SECTION K. 663 
This is brought about by buds in the axils of some (generally two) of the 
upper foliage leaves developing and producing lateral shoots, each termi- 
nating in a flower, which blooms shortly after that of the main axis. 
The leaves subtending these lateral (secondary) flowering shoots undergo 
reduction, eventually becoming bracts, and those (two in number, as a rule) 
borne on the secondary axes themselves are also usually reduced structures, 
being the precursors of the pair of bracteoles so general to the flower stalk 
(pedicel) of Dicotyledons. Examples showing this initial stage in the evolu- 
tion of the inflorescence are afforded by Calycanthus; Paonia albiflora; 
Trollius; Rosa, ete. 
An advance from the simple dichasium may come about by the pro- 
duction of fertiary floral shoots from the axils of the leaves (bracteoles) of 
the secondary ones, and this branching may be continued so as to form 
higher orders of axes. In this way arise the lax forking inflorescences 
(compound or continuous dichasia they may be called), characteristic of 
species of Ranunculus and Potentilla, and especially of the family Cary- 
ophyllacee. Often the branching progresses at a quicker rate on one side 
than on the other; if this be accentuated till the branching becomes one- 
sided from the commencement, a continuous monochasium results; and 
further by the flowers assuming a lateral instead of a vertical position, a 
sympodium comes to be formed. Thus originate the complex sympodial 
cymose inflorescences of the Boraginacesze and other families. 
The pleiochasium or panicle as the first stage in the evolution of racemose 
inflorescences.—If the buds in the axils of several leaves on the main axis, 
instead of only two or three, produce lateral shoots each ending in a flower, 
a type of inflorescence known as the pleiochasiwm will arise. These 
secondary axes are generally branched to some extent dichasially. Many 
of these inflorescences have been grouped under the name panicle, tho 
stumbling-block of the descriptive morphologist. The earliest form of this 
inflorescence is one in which the terminal flower of the main axis expands 
first ; the lateral flowers then open somewhat acropetally. Examples :—- 
Helleborus fetidus; Dicentra formosa; Rubus fruticosus; Campanula spp. 
Further steps towards the evolution of true racemose inflorescences 
take place as follows :— 
(1) An increase in the number of laterals, with the result that the 
terminal flower no longer blooms first. 
(2) Suppression of tertiary branching with the production of a raceme 
with a terminal flower. 
(3) Finally the terminal flower, often together with the upper part of 
the inflorescence, is arrested in its growth, and in the end aborts with the 
formation of a true raceme. 
The evolution of racemose inflorescences according to the above plan has 
occurred independently in several lines of descent ; as examples Delphinium, 
Campanula, and the Fumarioidee may be mentioned. 
Thus, in the author’s opinion, racemose inflorescences have always 
proceeded from cymose ones, and are therefore, on the whole, a later type. 
Hence the Composite, usually regarded as the highest group of flowering 
plants, may be said to have the most evolved kind of inflorescence, the head 
or capitulum. These heads in various members of the family are clustered 
together so as to form compound inflorescences, which arise phylogenetically 
in a manner corresponding to what has been shown for simple inflorescences 
—first cymose aggregates appear, then racemose ones, culminating in the 
compound head, possessed by the genus Echinops. 
Solitary Axillary Flowers.—Two kinds at least of these are dis- 
tinguishable. 
(a) The type commonly, but not exclusively, exhibited by climbing 
and trailing plants, in which single flowers are produced in ascending 
order from the axils of the foliage leaves. Such an arran~>ment can be 
