Inflorescence racemed or paniculate; glumes four, first two glumes unequal 4. Panicum. Inflorescence panicled, branches of panicle produced beyond the uppermost spikelet; glumes four, the first being minute and hyaline 5. Chamaeraphis. Spikelets unisexual and dioecious 6. Spinifex. CC. Spikelets awned. Glumes four, second glume broadly fimbriate with hairs; palea of the third glume short and deeply cleft, fourth glume awned 7. Axonopus. BB. Spikelets involucellate 8. Setaria. AA. Spikelets not jointed but continuous. Spikelets in involucelled deciduous fascicles. Involucre of bristles free 9. Pennisetum. Involucre of bristles united 10. Cenchrus. 1. Paspalum, _L._ These are annuals or perennials. The spikelets are plano-convex, orbicular to oblong, obtuse, secund, 2-ranked on the flattened or triquetrous rachis of the spike-like branches of a raceme, one-flowered and falling off entire from the very short or obscure pedicels. There are three glumes, all more or less equal and similar. The first and the second glumes are membranous, alike and as long as the third, the second glume is usually epaleate and occasionally with a minute palea. The third glume is chartaceous to sub-coriaceous and paleate. Lodicules are two and small. Stamens are three. The styles are slender and distinct with plumose stigmas exserted at the top of the spikelet. Grain is tightly enclosed in the third glume and its palea. [Illustration: Fig. 69.--Paspalum scrobiculatum.] =Paspalum scrobiculatum, _L._= This is an annual grass, with stems tufted on very short rhizomes, erect or very shortly bent at base, glabrous, bifariously leafy and varying in height from 1 to 3 feet or more. _Leaf-sheaths_ are compressed, glabrous, loose, keeled, mouth hairy or not. The _ligule_ is a short thin membrane. The _nodes_ are glabrous. The _leaf-blade_ is linear-lanceolate, finely acuminate, keeled with a distinct midrib, and with very minutely serrulate margins, 6 to 18 inches by 1/12 to 1/3 inch. The _inflorescence_ consists of 2 to 5 sessile alternate spikes, usually distant and spreading and varying in length from 1 to 8 inches; the rachis is flattened and winged. The _spikelets_ are either orbicular or ovate-oblong, as broad as the rachis, glabrous, closely imbricating in two rows (rarely in three or four rows), sessile or rarely geminate on a common pedicel.