Digitaria horizontalis Willd.

Map

Spikelets

Description

Plants of indefinite duration; sprawling. Culms to 1 m, erect portion 20-25 cm, decumbent, rooting and branching freely at the nodes. Sheaths usually with scattered papillose-based hairs, hairs more abundant on the lower sheaths; ligules 1.5-1.8 mm, erose; blades 3-14 cm long, 3-9 mm wide, evenly, often densely pubescent adaxially, hairs papillose-based. Panicles with 2-14 spikelike branches attached to 4-15 cm rachises, lower branches whorled, upper branches often paired or solitary; lower nodes with hairs more than 0.4 mm; primary branches 4-12 cm, axes 0.4-0.7 mm wide, wing-margined, wings at least 1/2 as wide as the midribs, often with scattered 1-4 mm hairs proximally, bearing spikelets in unequally pedicellate pairs on the proximal and middle portion of the branches; secondary branches rarely present; shorter pedicels 0.3-0.5 mm; longer pedicels 1.3-2 mm. Spikelets homomorphic, 2.1-2.4 mm, narrowly ovate. Lower glumes 0.1-0.2 mm; upper glumes 1-1.1 mm, 1/3 – 1/2 as long as the spikelets, 3-veined, margins and apices ciliate; lower lemmas about as long as the spikelets, lanceolate, 7-veined, lateral 3 veins on each side unequally or equally spaced, smooth or scabrous over the distal 1/3, lemma margins and the region between the second and third veins densely pubescent, hairs 0.05-0.1 mm, white; upper lemmas slightly shorter than the lower lemmas, yellowish or grayish when immature, becoming light brown at maturity, minutely striate. Caryopses about 1.8 mm, tan. 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_horizontalis )