1 Inflorescences an open panicle (as long as wide); spikelets solitary (or paired or in 3’s) on long or short pedicels; pedicels mostly > 2× as long as the spikelets, mostly spreading (sometimes distally appressed on branches); the entire panicle usually detaching at maturity

1 Inflorescences of digitate or sub-digitate primary branches, or primary branches alternately arranged along a central axis; with (1) 2-3 (or more) spikelets per node on primary branches, arranged in two rows along one side of the branch; spikelets appressed on branches; the entire inflorescence not detaching at maturity.

  2 Inflorescences of primary branches alternately arranged along a central axis; all the rachilla internodes more or less conspicuously elongated, hence upper florets stipitate; upper lemmas dark brown at maturity; spikelets 3.0-6.6 mm long, densely short to long pubescent, hairs generally exceeding the length of the spikelet and hairs spreading at maturity; hairs smooth-walled, with acute apices

  2 Inflorescences of digitate or sub-digitate primary branches, or primary branches alternately arranged along a central axis; no conspicuous elongated rachilla internodes, upper floret not stipitate; upper lemmas pale yellow, tan, gray, purple-tinged, purple, brown or dark brown; spikelets 1.3-4.1 mm long, glabrous to variously pubescent; hairs various, smooth or verrucose walled, with acute or dilated apices.

    3 Rachis of each raceme narrow, trigonous, only slightly (if at all) winged.

      4 Spikelets in 2s on the middle portions of the primary branches, the pedicels not adnate; upper lemmas gray, yellow, and/or purple-tinged when immature, purple at maturity

      4 Spikelets in groups of 2-5 on the middle portions of the primary branches, the longer pedicels often adnate to the primary branch for a portion of their lengths; upper lemmas brown when immature, dark brown at maturity.

        5 Spikelets 1.7-2.2 mm long; plants 3-10 dm tall; racemes to 10 cm long; upper sheaths glabrous, lower sheaths glabrous to sparsely pilose

        5 Spikelets 2.0-2.8 mm long; plants 8-15 dm tall; racemes to 25 cm long; upper sheaths glabrous or pilose, lower sheaths densely pilose

    3 Rachis of each raceme broad (0.5-1 mm wide), winged, the wings as wide as or wider than the rachis proper.

          6 Lower sheaths glabrous; second glume 0.75-1× as long as the first glume (which may be absent or a veinless, membranous rim); fertile lemma dark brown or black at maturity (or pale brown or gray in D. longiflora).

             7 Hairs of the spikelet minutely capitate; second glume ca. 1× as long as the first glume; spikelets 1.7-2.3 mm long

             7 Hairs of the spikelet not minutely capitate; second glume ca. 0.75× as long as the first glume; spikelets 1.2-1.7 mm long

          6 Lower sheaths pilose; second glume 0.3-0.6× as long (to 0.8× as long in D. ciliaris) as the first glume; fertile lemma white, tan, or grayish-brown at maturity.

               8 Spikelets 1.5-1.8 mm long, villous with crinkled hairs; pedicels glabrous, terete in cross-section

               8 Spikelets (1.7-) 2.4-4.1 mm long, glabrous, scabrous, or pubescent with straight hairs; pedicels scabrous, 3-angled in cross-section; [section Digitaria].

                 9 Spikelets (1.7-) 2.5-3.4 mm long, averaging 3.0 mm long or shorter; leaf blades pilose over the upper surface

                 9 Spikelets 2.6-4.1 mm long, averaging 3.1 mm long or longer; leaf blades glabrous except for a few hairs on the upper surface at the base.

                   10 Lower lemma of the sessile spikelet with 5 equidistant nerves; lowermost inflorescence node glabrous or pubescent with hairs < 0.4 mm long; apex of the first glume rounded to truncate

                   10 Lower lemma of sessile spikelet with the lateral nerves crowded to the margins; lowermost inflorescence node pubescent with hairs > 0.4 mm long; apex of the first glume acute