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Digitaria radicosa

(Trailing Crabgrass)

Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in Chinese:

Gen Ma Tang, Hong Mao Ling (As D Timorensis)

Common Names in English:

Trailing Crabgrass, Timorese Crabgrass

Common Names in Japanese:

Kome Hishiba

Description

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Genus Digitaria

Annual or perennial . Culms erect or decumbent , occasionally stoloniferous . Leaf blades linear or linear-lanceolate; ligule membranous. Inflorescence of digitately arranged racemes , sometimes on a short axis or with secondary branchlets , very rarely paniculate ; spikelets usually in groups of 2-3(-4), imbricate to effuse, the latter often on notably long and unequal pedicels. Spikelets puberulous to villous , typically in stripes between the well-defined veins, rarely glabrous ; lower glume absent or reduced to a little scale up to 1/4 spikelet length; upper glume variable; lower lemma usually ± equal to spikelet; upper floret pallid to black, apex subacute to acuminate, rarely apiculate . x = 9.

About 250 species:tropical and warm-temperate regions of the world; 22 species (three endemic) in China.

Digitaria has been traditionally divided on the nature of the spikelet hairs, which may be clavate , capitate, verrucose (warty, appearing beaded), or with crooked tips . As good magnification is required to see these features, the grouping of the spikelets on the raceme is a more practical aid to identification. Many species have regularly paired spikelets, which present no difficulty. In those species where the spikelets are grouped in clusters of 3 or more, care must be taken, as often the longest pedicel of a group is partially fused to the rachis so that the spikelets appear alternately paired and single, or sometimes one spikelet may be vestigial, or the spikelets may be paired toward the raceme tips.

Many species are very variable in spikelet pubescence and lemma nervation, even within a single raceme. Additionally, there are a number of complexes of intergrading species, so intermediates may occasionally be encountered. This has led to the publication of many superfluous names .[1]

Physical Description

Species Digitaria radicosa

Annual . Culms slender, trailing , branching, 30-50 cm tall, glabrous . Leaf sheaths usually glabrous; leaf blades linear-lanceolate, 2-6 × 0.3-0.7 cm, abaxial surface scabrous , adaxial surface glabrous, pubescent or papillose-pilose at base ; ligule 0.75-2 mm. Inflorescence digitate; racemes 2-3(-4), slender, 4-10 cm; spikelets paired , loosely imbricate by about half their length ; rachis triquetrous , narrowly winged , ca. 0.6 mm broad, margins smooth or almost so. Spikelets narrowly lanceolate, 2.8-3 mm; lower glume triangular, 0.2-0.3 mm; upper glume narrow, long triangular, 1/3-2/3 as long as spikelet, 1-3-veined, villous throughout; lower lemma as long as spikelet, 5-7-veined, a broad intervein space on either side of midvein , lateral veins very close together near margin, appressed silky pubescent, very rarely with a ciliate fringe , never setose ; upper lemma yellowish at maturity, narrowly lanceolate. Anthers 0.5-1 mm. Fl. and fr. summer-autumn. 2n = 18. [source]

This species is related to Digitaria ciliaris, but differs in its slender, trailing habit, fewer digitate racemes with smooth-edged rachis, and narrow spikelets with contiguous lateral veins in the lower lemma, which thereby appears 3-veined. [source]

Habit: Graminoid

Habitat

Moist grasslands, roadsides, weedy places[2].

Biology

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Reproduction

Duration: Annual

Taxonomy

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Synonyms

D. formosana Rendle • D. formosana var. hirsuta (Honda) Henrard • D. radicosa var. hirsuta (Honda) C. C. Hsu • D. tenuispica Rendle • D. timorensis (Kunth) Balansa • Digitaria chinensis Hornemann var. hirsuta (Honda) Ohwi • P. timorense Kunth • Panicum formosanum (Rendle) Makino & Nemoto • Panicum radicosum J. Presl • Reliq. Haenk. 1: 297. 1830 • S. formosana var. hirsuta Honda. • Syntherisma formosana (Rendle) Honda

Notes

Name Status: Accepted Name .

Last scrutiny: 15-Mar-2000

Similar Species

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Members of the genus Digitaria

ZipcodeZoo has pages for 53 species, subspecies, varieties, forms, and cultivars in this genus:

D. abyssinica (African Couchgrass) · D. arenicola (Fall Witchgrass) · D. argillacea (Tropical Crabgrass) · D. bicornis (Asia Crabgrass) · D. californica (Arizona Cottontop) · D. ciliaris (Fingergrass) · D. cognata (Carolina Cottontop) · D. cognata var. cognata (Carolina Crabgrass) · D. cognata var. pubiflora (Carolina Crabgrass) · D. cruciata (Crabgrass) · D. diagonalis (Brown-Seeded Finger Grass) · D. didactyla (Crabgrass) · D. dolichophylla (Caribbean Crabgrass) · D. eggersii (Eggers' Crabgrass) · D. eriantha (Pangola Grass) · D. eriantha subsp. eriantha (Crabgrass) · D. eriantha subsp. pentzii (Woolly Fingergrass) · D. exilis (Fonio) · D. filiformis (Slender Crabgrass) · D. floridana (Florida Crabgrass) · D. fuscescens (Yellow Crabgrass) · D. gracillima (Long-Leaf Crabgrass) · D. henryi (Henry´s Crabgrass) · D. hitchcockii (Short-Leaf Crabgrass) · D. horizontalis (Jamaica Crabgrass) · D. iburua (Black Fonio) · D. insularis (Sourgrass) · D. ischaemum (Small Crabgrass) · D. ischaemum var. ischaemum (Small Crabgrass) · D. longiflora (India Crabgrass) · D. milanjiana (Madagascar Crabgrass) · D. natalensis (Natal Crabgrass) · D. nuda (Naked Crabgrass) · D. panicea (Millet Crabgrass) · D. patens (Texas Cottontop) · D. pauciflora (Florida Pineland Crabgrass) · D. pubiflora (Carolina Crabgrass) · D. radicosa (Trailing Crabgrass) · D. sanguinalis (Crabgrass) · D. seriata (Crabgrass) · D. serotina (Blanket Crabgrass) · D. setigera (East Indian Crabgrass) · D. setivalva (Crabgrass) · D. similis (Roadside Crabgrass) · D. simpsonii (Isle-Of-Pines Crabgrass) · D. swalleniana (Swallen's Crabgrass) · D. ternata (Black-Seeded Crabgrass) · D. texana (Texas Crabgrass) · D. tomentosa (Woolly Crabgrass) · D. umfolozi (Crabgrass) · D. velutina (Annual Couchgrass) · D. villosa (Shaggy Crabgrass) · D. violascens (Violet Crabgrass)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal November 13, 2007:

Identifiers

Footnotes

  1. Shou-liang Chen & Sylvia M. Phillips "Digitaria". in Flora of China Vol. 22 Page 1, 500, 539. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
  2. "Digitaria radicosa". in Flora of China Vol. 22 Page 540, 542, 543. Missouri Botanical Garden Press. Online at EFloras.org. [back]
Last Revised: 7/15/2012