Fig. 209.—The Bag tied over a Flower.
Fig. 210.—The fig is a hollow torus with flowers borne on the inside, and pollinated by insects that enter at the apex.
CHAPTER XX
FLOWER-CLUSTERS
Origin of the Flower-cluster.—We have seen that branches arise from the axils of leaves. Sometimes the leaves may be reduced to bracts and yet branches are borne in their axils. Some of the branches grow into long limbs; others become short spurs; others bear flowers. In fact, a flower is itself a specialized branch.
Fig. 211.—Terminal Flowers of the Whiteweed (in some places called ox-eye daisy).
Flowers are usually borne near the top of the plant. Often they are produced in great numbers. It results, therefore, that flower branches usually stand close together, forming a cluster. The shape and the arrangement of the flower-cluster differ with the kind of plant, since each plant has its own mode of branching.
Certain definite or well-marked types of flower-clusters have received names. Some of these names we shall discuss, but the flower-clusters that perfectly match the definitions are the exception rather than the rule. The determining of the kinds of flower-clusters is one of the most perplexing subjects in descriptive botany. We may classify the subject around three ideas: solitary flowers, centrifugal or determinate clusters, centripetal or indeterminate clusters.
