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The fruit is like that of most grasses, enclosed in a folded leaf, the bract (or glume), which in these particular cases is produced into a very long fine tapering hair or awn. This awn is sensitive to changes in the _moisture_ of the air. It is strongly hygrometric: in wet weather it straightens itself, and it coils into corkscrew spirals in dry weather. The widened part of the base, which contains the grain, tapers into a sharp, very hard point; upon this there are, on the outside, many stiff hairs, which point backwards away from the sharp tip.