Digitaria scalarum (Schweinf.) Chiov.

Map

Inflorescence

Plant

Habit

Spikelets

Landscape

Collar

Rhizomes

Description

Plants perennial; rhizomatous, mat-forming. Culms 5-80 cm, decumbent, occasionally rooting at the lower nodes, branching freely at the base, erect portion 20-40 cm; nodes 2-6. Sheaths of midculm leaves glabrous or hirsute, with papillose-based hairs; ligules 0.8-2.1 mm; blades 4-15 cm long, 3-10 mm wide, glabrous or sparsely pubescent with papillose-based hairs. Panicles with 2-25 spikelike primary branches on 1-9 cm rachises; primary branches 2-11 cm, axes not winged or narrowly winged, wings less than 1/2 as wide as the midribs, bearing spikelets in unequally pedicellate pairs; secondary branches rarely present; pedicels not adnate to the branch axes. Spikelets 1.5-2.5 mm long, 0.8-0.95 mm wide, ovate-elliptic to broadly elliptic, usually plump, usually purple-tinged. Lower glumes absent or to 0.8 mm and acute; upper glumes 1.2-2.4 mm, from 0.8 times as long as to almost equaling the spikelets, glabrous, 3-7-veined, veins usually prominent; lower lemmas 1.5-2.5 mm, usually glabrous, occasionally obscurely puberulent on the margins or, very rarely, distinctly pubescent, 7-veined, veins usually prominent; upper lemmas light brown, gray, and purple. 2n = 36.
(Description source: Barkworth, M.E., Capels, K.M., Long, S. & Piep, M.B. (eds.) 2003. Flora of North America, north of Mexico. Volume 25. Magnoliophyta: Commelinidae (in part): Poaceae, Part 2. Oxford University Press, New York. 783 pp http://floranorthamerica.org/Digitaria_scalarum )

A rhizomatous perennial, rhizome conspicuously well developed, growing deeply, straight with vertically growing offshoots, much branched at groundlevel, sometimes stoloniferous. Culms (10)20–40 cm., ascending from a creeping base, glabrous, nodes dark, glabrous or hairy. Leaf sheaths often with many bulbous based bristles, sometimes scaberulous. Ligule 1–3 mm. long, truncate, erose or subentire. Leaf laminae 5–10 × 0.3–0.6 cm., linear, flat or involute, glabrous or sometimes loosely hairy on both surfaces, scabrous along the crisped margin. Inflorescence composed of (2)4–10(12) racemes, (1)3–10 cm. long, erect to patent, sometimes branched at the base, solitary along a well developed common axis. Rhachis triquetrous, narrowly winged, up to 0.4 mm. broad, smooth to scaberulous, with scaberulous margins. Pedicels 2 nate, 0.5–2.5 mm. long, subterete to triangular, scaberulous, scarcely broadened at the apex. Spikelets (1.6)1.7–2.2(2.4) mm. long, oblong-ovate, swollen. Inferior glume 1/10–1/4 of the spikelet, conspicuously heteromorphic, often erose or truncate, nerveless, glabrous, hyaline, sometimes purplish. Superior glume c.4/5 of to as long as the spikelet, ovate to oblong, 5(7)-nerved, glabrous or with some short, fine hairs in a marginal row, pale green, often purplish tinged. Inferior lemma as long as the spikelet, ovate-oblong with recurved margins, 7-nerved, glabrous or with a marginal row of short, fine hairs, pale green, often purplish tinged. Superior lemma as long as the spikelet, ovate-oblong, apiculate, swollen, bluish green to dark brown. Habitat: Sandy flood plains, wet spots in disturbed sandy soils, weed in gardens.
(Description source: Goetghebeur, P. & Van der Veken, P. 1989. Digitaria. In: Launert, E. & Pope, G.V. (eds.), Flora Zambesiaca. Vol. 10. Part 3. British Museum of Natural History, Lon - don. 152 pp )