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 upwards (Fig. 213). The raceme may be terminal to the main branch; or it may be lateral to it, as in Fig. 214. Racemes often bear the flowers on one side of the stem, thus forming a single row.

When a centripetal flower-cluster is long and dense and the flowers are sessile or nearly so, it is called a spike (Fig. 215). Common examples of spikes are plantain, mignonette, mullein.

{{small caps|Fig. 213.—{{small caps|Raceme of Currant.}} Terminal or lateral?

{{small caps|Fig. 214.—Lateral Racemes}} (in fruit) {{small caps|of Barberry}}.

{{missing image}} {{small caps|Fig. 215.—Spike of Plantain.}}

A very short and dense spike is a head. Clover (Fig. 216) is a good example. The sunflower and related plants bear many small flowers in a very dense and often flat head. Note that in the sunflower (Fig. 189) the outside or exterior flowers