Digitaria velutina

Name and classification

Digitaria velutina (Forssk.) P. Beauv.
Family Poaceae, Tribe Paniceae

Common names

velvet fingergrass, annual couchgrass

Disseminule

spikelet, disarticulation below the glumes

Description

Spikelets of 1 fertile floret and 1 basal sterile lemma. Spikelets elliptic to lanceolate, dorsally compressed, plano-convex, 1.5–2.1 mm long, 0.5–0.6 mm wide. Pubescent, with short to long hairs between nerves on upper glume and sterile lemma. Glumes dissimilar; lower glume a small scale or absent; upper glume membranous, 1.2–1.6 mm long. Sterile lemma membranous, as long as spikelet. Fertile lemma gray to brown at maturity, cartilaginous, striate, as long as spikelet, with flat margins covering much of palea.

Identification considerations

Fertile lemmas in the genus Digitaria are flat and thinner at the margins. See Digitaria abyssinica (Hochst. ex A. Rich.) Stapf.

Similar species

Digitaria horizontalis Willd. (non-FNW)

Distribution

widespread in tropical Africa, including South Africa; Asia: China, India, Japan, Korea, Malaysia, Taiwan; Oceania: Micronesia; North America: Costa Rica, United States

native to eastern Africa

Habitat

sandy soils, damp places; fields, plantations, open brush

General information

Digitaria velutina is a slender, annual grass, up to 100 cm tall. It is a quickly invading, common weed of arable land in Africa. Propagation is by the grains, which are highly viable. This grass has been used as a forage plant.

spikelets, florets, caryopses, and portion of inflorescence; photo by Mark Thurmond

spikelets, florets, caryopses, and portion of inflorescence; photo by Mark Thurmond

spikelets, florets, and caryopses; photo by Mark Thurmond

spikelets, florets, and caryopses; photo by Mark Thurmond

spikelets in dorsal view showing upper glume and fertile lemma

spikelets in dorsal view showing upper glume and fertile lemma

spikelets in ventral view showing sterile lemma

spikelets in ventral view showing sterile lemma

A, spikelet in ventral view showing sterile lemma; B, spikelet in dorsal view showing upper glume and fertile lemma; C, floret in ventral view showing palea and margins of lemma; D, floret in dorsal view showing lemma; E, caryopsis in ventral view; F, caryopsis in dorsal view; drawing by Lynda E. Chandler

A, spikelet in ventral view showing sterile lemma; B, spikelet in dorsal view showing upper glume and fertile lemma; C, floret in ventral view showing palea and margins of lemma; D, floret in dorsal view showing lemma; E, caryopsis in ventral view; F, caryopsis in dorsal view; drawing by Lynda E. Chandler