174 Botany

intensified. For wind-pollination, too, the massing
together of flowers is an advantage; for, when the
stigmas are clustered in groups, as is the case with
the maize, there is a better chance of their arresting
the pollen grains than if they were arranged singly.
Moreover, in the latter case, to adequately display the
flowers, more energy must be expended on the produc-
tion of the flower stalks.

The term inflorescence denotes the grouping and
arrangement of the flowers produced on any one floral
axis. The main stalk of an inflorescence is usually
called the peduncle but where it forms an unbranched
leafless axis arising from the midst of radical leaves
(i.e. leaves springing from the ground) and bears
flowers at its apex, as in the cowslip, it is known as a
scape. The stems of individual flowers in an inflor-
escence producing more than a single flower are termed
pedicels.

Bracts (Fig.111) are modified leaves, which, when
present, usually protect the flowers of an inflorescence
while in the bud. In the violet a small bract springs
from either side of the peduncle. In the arum a large
white flower-like bract known as a spathe protects
the spike-like inflorescence within. The dandelion and
most other members of the daisy family have a ring
of bracts forming what is called an involucre, situated
immediately below the inflorescences.

Forms of Inflorescence. Inflorescences may be
either definite or indefinite, the latter being by far the
commoner.

In an indefinite inflorescence (Fig.s 112-113A) the
youngest flowers and buds are at the end of the
peduncle. Those produced nearer the base open first,
and there is an indefiniite succession of blooms, each
produced nearer the tip than the one that opened
before it. In other words, the flowers are produced in
acropetal (Gk. akros apex and peto I seek) succession.