The Gramineae

In the preceding chapter, we considered the structure and anthesis of the reproductive shoot in grasses, omitting the more aberrant forms. Even when the field was thus limited, we met with a series of instances in which the divergence from the ‘typical’ Monocotyledonous floral diagram—or even from the more restricted scheme developed in the Bambuseae—followed the direction of fusion or suppression of parts. Examples which may be recalled are: fusion of the outer empty glumes; absence of the third lodicule; fusion of the remaining pair; absence of one whorl of stamens; loss of two of the three stamens of the remaining whorl; and the uniovular character of the gynaeceum. In this chapter we shall continue to study the subject of reduction, both in typical grasses and in the more peculiar examples in which the factor is specially apparent. It is remarkable that this reduction-trend—though itself, in the last analysis, a negative character—has led to an exceedingly varied series of forms.

Certain modifications in the outer empty glumes may first be discussed. The inflorescences of the curious little grass, Cornucopiae cucullatum L., have delicate cupules, each of which encloses one spikelet; they are drawn in Fig. 72, D and E, while the structure is shown in section in F–H. Unlike certain former writers, I interpret the cupule as consisting of the first and second outer empty glumes in a state of fusion.