Journal of Proceedings. lxxxix
which come after will be lateral or axillary. If the terminal bud be
abortive, or if it continue to grow in prolongation of the stem, all the
flowers will be lateral in their relation to the main axis, but may be
either terminal or lateral in their relation to the branch which bears
them. Let us look at the results of these contingencies.
In the King-cup (Caltha palustris) we have a stem whose terminal
bud becomes a flower, and a bud in the axil of the uppermost leaf or bract
is also a flower bud. This, the lateral, axillary or sub-terminal flower,
does not expand so soon as the terminal flower. It is on a simple pedicel,
which bears no bract nor any modification of a leaf below or outside the
calyx, nor has it any capacity for branching. It is well to observe these
particulars as they serve to distinguish this mode of inflorescence properly
definite from any which can fairly be called centrifugal. From the axil
of a lower leaf grows another branch, which, like the main axis, bears a
flower at its top with a leaf or bract below it, in the axil of which is a
sub-terminal flower.
It may appear that in such cases as the above, where there is a stem
with many branches, each of which is capable of bearing several flowers,
every such branch ought to be considered as a separate individual, and
that the relation of such branches to each other and to the main stem
which bears them ought to be regarded as a matter quite distinct from
the arrangement of the flowers upon each peduncle. Looking at the
subject from this point of view, I arrived at the conclusion that the
arrangement of individual flowers on a peduncle or flowering branch is of
more importance as to natural affinity than the mode in which peduncles
or flowering branches are placed on the main stem.
The inflorescence of the King-cup is definite, but not centrifugal, for
(1) the pedicel of the uppermost lateral or sub-terminal flower is simple,
and with no capacity for branching ; (2) the same uppermost lateral or
sub-terminal flower does not commonly open so soon as that which
terminates the branch immediately below it. In both of these particulars
the inflorescence of the King-cup is in striking contrast to that of the
Stitchwort (Stellaria) or the Campion (Lychnis), which is strictly
centrifugal.
That the annual flowering stem of the King-cup, with all the branches
growing on it, should be regarded as forming collectively a single system,
all parts of which are related to each other, may be inferred from the
facts of an apparent order existing in the expansion of their several
flowers, and of the greater capacity for branching observed in those
branches which spring from the lower part of the stem in comparison
with those from its upper part.
The flowering stem of the Columbine (Aquilegia vulgari)), with its
branches, forms an inflorescence more compact than that of the King-
cup, but with a general resemblance to it; differing, however, in that the
uppermost lateral flower-stalk is not a simple pedicel but a peduncle
capable of branching, usually bearing two bracts below the flower, and
often with flowers in their axils on stalks which may be properly called
tertiary axes. In that the flower on the top of the main stem is the first
to open, and that which terminates the secondary axis comes before that
on the tertiary axis, this plant resembles those whose inflorescence is
properly centrifugal; but differs, inasmuch as of several branches or
secondary axes that which is lowest is often longest, bears most flowers,
and is forwarder in their expansion than any of the branches of the same
rank which grow above it. A source of error exists, however, in that
while three or more branches rise to a level with the main axis, opening
their flowers in a centripetal order as compared with each other, another
branch or two may sometimes be found lower down which flower later,
as following a centrifugal order.