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 open first. Another special form of spike is the catkin, which usually has scaly bracts,the whole cluster being deciduous after flowering or fruiting,and the flowers (in typical cases) having only stamens or pistils. Examples are the "pussies" of willows (Fig. 182) and flower-clusters of oak (Fig. 180), walnuts (Fig. 204), poplars.

When a loose, elongated centripetal flower-cluster has some primary branches simple, and others irregularly branched, it is called a panicle. It is a branching raceme. Because of the earlier growth of the lower branches, the panicle is usually broadest at the base or conical in outline. True panicles are not very common.

When an indeterminate flower-cluster is short, so that