Digitaria filiformis
Plants annual, or short-lived perennials; cespitose, not rhizomatous. Culms (10)25-150 cm, erect or decumbent, branching, sometimes rooting at the lower nodes; nodes 3-6. Sheaths keeled, basal sheaths usually with papillose-based hairs, rarely glabrous; ligules 0.3-1.5 mm; blades 2-18 cm long, 1-6 mm wide, flat or involute, glabrous, scabrous, or pilose. Panicles with 2-7 spikelike primary branches, these digitate or the rachises to 1 cm; longest primary branches 20-25 cm, axes triquetrous, not winged, with spikelets in unequally pedicellate groups of 3(-5) on the basal ½ (J. Wipff, pers. comm.). Spikelets 1.3-2.8 mm. Lower glumes absent or to 0.1 mm; upper glumes 1-2 mm long, from 3/4 to almost as long as the spikelets, almost glabrous or sparsely to densely pubescent with clavate to capitate hairs (use 20x magnification), glume apices rounded; lower lemmas equaling the spikelets, glabrous or glandular-pubescent, 5-7-veined, veins unequally spaced, outer 3 veins on each side closer to each other than the midvein is to the inner lateral veins; upper lemmas 1.3-2 mm, apiculate, dark brown at maturity; anthers 0.3-0.6 mm. 2n = 36, 54.
Distribution
Conn., N.J., N.Y., Del., D.C., W.Va., Fla., N.H., Tex., La., Tenn., N.C., S.C., Pa., Va., Ala., Mass., R.I., Ark., Vt., Ill., Ga., Ind., Iowa, Md., Kans., Okla., Ohio, Mo., Mich., Miss., Ky.
Discussion
Digitaria filiformis grows throughout the warmer parts of the eastern United States, van filifomis the most widespread of its varieties, extending into Mexico.
Selected References
None.
Lower Taxa
Key
| 1 | Lower lemmas glabrous | Digitaria filiformis var. laeviglumis |
| 1 | Lower lemmas pubescent. | > 2 |
| 2 | Basal leaf sheaths glabrous; cauline blades about 1 mm wide, folded or involute | Digitaria filiformis var. dolichophylla |
| 2 | Basal leaf sheaths with papillose-based hairs; cauline blades 1-6 mm wide, flat. | > 3 |
| 3 | Spikelets 1.3-1.9 mm long; panicle branches 3-13 cm long; culms 10-80 cm tall | Digitaria filiformis var. filiformis |
| 3 | Spikelets 2-2.8 mm long; panicle branches 10-25 cm long; plants 75-150 cm tall | Digitaria filiformis var. villosa |