Sub-class I. Glumaceae, Endl.
Characters.—Flowers disposed in spikelets, and enclosed within imbricated bracts. Ovary free, unilocular, containing one erect ovule. Fruit a caryopsis. Embryo at the base of farinaceous albumen.
This class includes two orders: 1. Gramineae, or glumaceous endogens with round stems, leaves having split sheaths, and embryo lying on the outside of the albumen. 2. Cyperaceae, or glumaceous endogens with angular stems, leaves with entire sheaths, and embryo included within the albumen.