Tribes
Andropogoneae (1-5) and Paniceae (6-11). Use the key to grass tribes on
pages 3-
1. Andropogon gerardii. A perennial bunchgrass with occasional short rhizomes, the ligule is a fringe of hairs on a dissected membrane, inflorescences comprise spikes of spikelet pairs, the spikes are close to being digitately arranged.
2. Andropogon hallii. A rhizomatous perennial that differs from the above by commonly producing rhizomes, bearing long hairs on the pedicels and inflorescence internodes, and inhabiting sandy soils, inflorescences comprise spikes of spikelet pairs, the spikes are close to being digitately arranged.
3. Andropogon scoparius. A perennial bunchgrass with occasional short rhizomes, the pedicellate spikelet of each spikelet pair is reduced to a small scale, inflorescences comprise spikes of spikelet pairs, with generally solitary spikes on branch ends.
4. Sorghum halapense. A rhizomatous perennial, the inflorescence is a panicle of spikelet pairs, the same as found in cultivated Sorghum.
5. Zea mays. Single-stemmed annuals, monoecious: staminate spikelet pairs in the terminal panicle, pistillate spikelet pairs on a woody cob in leaf axils.
6. Digitaria sanguinalis. Annual bunchgrass, the stems decumbent and rooting at lower nodes, nodes hairy, inflorescence of essentially digitate spikes.
7. Panicum capillare. Annual bunchgrass, the nodes, leaf sheaths, and ligules are distinctly hirsute, inflorescence an open panicle.
8. Panicum virgatum. A rhizomatous bunched perennial, inflorescence an open panicle, the spikelets are dorsally compressed but the glumes and lemmas are keeled.
9. Echinochloa crusgalli. Annual bunchgrass that has no ligule, inflorescences of contracted secund panicles, the sterile lemma bears the awn.
10. Setaria viridis. Annual bunchgrass, spikelets embedded in a bristly head and disarticulating from it.
11. Cenchrus longispinus. Annual bunchgrass with an inflorescence like the above genus but with bristles fusing around the spikelets to form a burr.