Indian Crabgrass

Digitaria fuscescens (J. Presl) Henrard differs from D. longiflora only by its glabrous spikelets and slightly longer, fractionally exserted upper floret. Most likely it is simply a glabrous variant of D. longiflora. It is widespread throughout the tropics, and although reported from S China, no specimens have been seen.

Digitaria fuscescens (Presl) Henr is doubtfully distinct, differing only in its glabrous spikelets. It occurs in Southeast Asia as far west as eastern India.

Perennials; culm stoloniferous, rooting at nodes, branching, internodes 1-2 cm long; flowering culm slender, ascending, 10-40 cm tall. Blade mostly 1-4 cm long, 3-5 mm wide, ovate-lanceolate, glabrous; sheath pubescent, shorter than internode; ligule membranaceous, 1-1.5 mm long, more or less truncate, erose. Inflorescence in digitate racemes, racemes 2-4, 3-8 cm long, usually curving outward; rachis flat, broadly wing-margined. 0.5-0.8 mm wide; pedicel terete. Spikelet 1.2-1.5 mm long, ellipical, pale, minutely pubescent near margins; lower glume absent; upper glume and lower lemma about equal, elliptic-ovate, acute, 5-veined; lower lemma 5-7-veined, marginal veins often faint, with lines of hairs along margins and interveins spaces except inner-most 3; anther ca. 0.7 mm long.

Annual or short-lived perennial, usually with slender, many-noded stolons. Culms ascending, leafy, 10–40 cm tall. Leaf sheaths pubescent or glabrous; leaf blades broadly linear, 2–5 × 0.2–0.4 cm, glabrous or papillose-pilose at base, apex acute; ligule 1–1.5 mm. Inflorescence digitate; racemes 2–3, arching at maturity, 2–5 cm; spikelets ternate; rachis ribbonlike, winged, 0.5–0.8 mm broad, midrib low and rounded; pedicels terete, smooth, with discoid tips. Spikelets elliptic, 1.2–1.5 mm, apex acuminate, hairs verrucose; lower glume absent; upper glume as long as spikelet, 5-veined, densely appressed-pubescent; lower lemma as long as spikelet, 7-veined, glabrous between middle and lateral veins, otherwise pubescent; upper lemma yellowish brown or pale gray, apex acuminate. Anthers 0.6–0.8 mm. Fl. and fr. Apr–Oct. 2n = 18.

Annual or sometimes short-lived perennial, varying from a prostrate creeper to a leafy upright plant; culms 10-60 cm high, ascending from a stoloniferous base. Leaf-blades 1-9 cm long, 1-5 mm wide, the blades and sheaths usually glabrous but occasionally hirsute. Inflorescence composed of 24 (typically 2) digitate racemes; racemes 1-10 cm long, the spikelets ternate on a ribbon-like winged rhachis with low rounded midrib; pedicels terete, smooth, with discoid or cupuliform tip. Spikelets narrowly ovate-elliptic, 1.2-1.8 mm long; lower glume a minute hyaline rim; upper glume as long as the spikelet, 5-nerved, with short appressed verrucose hairs between the nerves (sometimes glabrous between 1st and 2nd lateral nerves); lower lemma as long as the spikelet, 7-nerved, pubescent with verrucose hairs or these appressed and barely visible (sometimes glabrous beside midrib and between 2nd and 3rd nerves); fruit ellipsoid, pallid, light brown or light grey.

Widely distributed in the tropics of the Old World.

Tropics of the Old World. Taiwan, along riverbanks and roadsides or on dykes between rice-fields.

Fujian, Guangdong, Guizhou, Hainan, Hunan, Jiangxi, Sichuan, Taiwan, Yunnan [Bhutan, India, Indonesia, Malaysia, Myanmar, Nepal, Pakistan, Sri Lanka, Thailand, Vietnam; Old World tropics, America].

Distribution: Pakistan (Punjab); throughout the Old World tropics; introduced to the New World.

500-1100 m

Field margins, grasslands, weedy places; 600–1100 m.

Paspalum longiflorum Retz., Observ. Bot. 4: 15. 1786.

Paspalum longiflorum Retzius, Observ. Bot. 4: 15. 1786; Digitaria propinqua (R. Brown) P. Beauvois; Panicum longi-florum (Retzius) J. F. Gmelin; P. parvulum Trinius, nom. illeg. superfl.; P. propinquum R. Brown; Syntherisma longiflora (Retzius) H. C. Skeels.

Annuals, Perennials, Terrestrial, not aquatic, Rhizome elongate, creeping, stems distant, Stolons or runners present, Stems trailing, spreading or prostrate, Stems nodes swollen or brittle, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems mat or turf forming, Stems terete, round in cross section, or polygonal, Stems branching above base or distally at nodes, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Leaf blades more or less hairy, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence a panicle with digitately arranged spicate branches, Inflorescence with 2-10 branches, Inflorescence branches 1-sided, Inflorescence branches paired or digitate at a single node, Rachis winged, Flowers bisexual, Spikelets pedicellate, Spikelets dorsally compressed or terete, Spikelet less than 3 mm wide, Spikelets with 1 fertile flo ret, Spikelets with 2 florets, Spikelet with 1 fertile floret and 1-2 sterile florets, Spikelets 3 per node, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating below the glumes, Spikelets secund, in rows on one side of rachis, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 1 clearly present, the other greatly reduced or absent, Glumes distinctly unequal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glume surface hairy, villous or pilose, Glumes 4-7 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma similar in texture to glumes, Lemma 5-7 nerved, Lemma glabrous, Lemma body or surface hairy, Lemma rugose, with cross wrinkles, or roughened, Lemma apex acute or acuminate, Lemma awnless, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea about equal to lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Digitaria longiflora is a species of crabgrass. It is the wild progenitor of the West African domesticated crop Digitaria exilis.