Flower Branches, Clusters, and Inflorences
one flower borne at the end of an elongated stalk or
branch of the main axis of the plant, as in tulip and Magnolia
grandiflora (southern magnolia). [The peduncle is
the stalk which bears the single flower at the top (and
is also the main stem or axis of a flower cluster). The pedicel
is the stalk of an individual flower in a cluster.]
three or more flowers gathered closely together in
simple or branched groups to increase their
conspicuousness, such as in Pentas spp. (pentas),
Ligustrum japonicum (ligustrum), Pyracantha
coccinea (firethorn), Mangifera indica (mango),
and Dianthus barbatus (sweet William).
general term for the arrangement of flowers or groups of
flowers on a plant. There is great diversity in this
arrangement among different types of plants, but they
generally remain characteristic for a particular type
and may be useful in identifying species. There are two
main types of inflorescences, each of which is further
subdivided; they are the racemose type and the cymose
the axis of the inflorescence continues to grow (it is
an indeterminate inflorescence) and the flowers are
borne in the axes of the reduced leaves or bracts, with
the oldest flowers at the base and the newest flowers
near the growing tip.
flowers on short pedicels of about equal length along
the main axis, as in Antirrhinum majus (snapdragon)
and Allamanda cathartica (allamanda).
compound raceme (the branches have branches), with
individual flowers replaced by simple racemes, as in Lagerstroemia
indica (crape myrtle) and Murraya paniculata (orange
like a raceme, but flowers lack pedicels and are sessile
or almost sessile. Examples are Acalypha wilkesiana (copperleaf)
and Callistemon spp. (bottlebrush).
type of spike; a fleshy axis bearing the sessile,
generally fleshy flowers close together, commonly
surrounded and partially enclosed by a spathe .
Examples are Zantedeschia aethiopica (calla) and Anthurium
spike which normally produces only staminate or
pistillate flowers (see next chapter), and at maturity
falls away as a unit. Examples are Betula nigra (river
birch) and Quercus spp. (oaks).
pedicels of older flowers longer than those of younger
flowers, which brings all of them to nearly the same
level. Pedicels come from different points on the main
peduncle, giving the inflorescence a rather flat-topped
or convex look with the outside flowers opening first.
Examples are Iberis spp. (candytuft) and Ixora
short axis which causes pedicels to appear to arise from
a common point (umbrella-shaped). This gives the
inflorescence a knob-like look. The outer flowers open
first. Examples are Anethum graveolens (dill) and
Crinum spp. (crinum lily).
similar to umbels, but sessile flowers are very close
together. Heads may be globular or almost spherical as
in Cephalanthus occidentalis (buttonbush) and Trifolium
hybridum (alsike clover). What popularly passes for
a "flower" in the Compositae (Asteraceae) is
really an inflorescence with many small, true flowers,
such as in Helianthus annuus (sunflower). Ray flowers
form a fringe of radiating irregular, asymmetrical
flowers (see chapter 8) on the edge of the head. Disk
flowers cover the remainder of the head and are
regular, symmetrical, and usually less showy. Heads may
also have flowers which are all irregular with no
differentiation into rays and disks.
cluster or whorl of bracts or leaves directly under a
flower or a cluster of flowers which is often
conspicuous. They are often found under umbels and
heads. Examples are Helianthus annuus (sunflower)
and the cups of acorns in Quercus spp. (oaks).
Upward growth of the floral axis is stopped early by the
development of a terminal flower. The first flower to
open (the oldest) is at the tip; with younger flowers
appearing lower down on the axis. The floral axis ceases
to elongate after the first flower opens, and is
therefore a determinate inflorescence.
one terminal flower and two or more side flowers coming
from the end of the axis. Examples are Plumeria spp.
(frangipani) and Solanum seaforthianum (Brazilian
floral axis curves over, carrying the flowers along the
top of the curve, as in Heliotropium spp.
flowers are very closely crowded on almost the same
plane (in a tight bundle or group), as in Dianthus
barbatus (sweet William).
flowers or clusters of flowers are carried on the ends
of the axis or branches, as in Magnolia grandiflora (southern
magnolia) and Nerium oleander (oleander).
flowers or clusters of flowers arise at the junction of
the stem or axis and the leaf, as in Catharanthus
roseus (periwinkle), Callicarpa americana (beautyberry),
and Hibiscus rosa-sinensis (hibiscus).
plants, such as Ixora coccinea (ixora), have both
terminal and axillary flowers.
Handbook for Florida, Revised Edition, Kathleen
C. Ruppert, January 1999 -- This document is copyrighted
by the University of Florida, Institute of Food and
Agricultural Sciences (UF/IFAS) for the people of the
State of Florida. UF/IFAS retains all rights under all
conventions, but permits free reproduction by all agents
and offices of the Cooperative Extension Service and the
people of the State of Florida. Permission is granted to
others to use these materials in part or in full for
educational purposes, provided that full credit is given
to the UF/IFAS, citing the publication, its source, and
date of publication.