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Digitaria ischaemum

(Small Crabgrass)

Overview

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Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in Chinese:

Zhi Xue Ma Tang

Common Names in Danish:

Liden Fingeraks

Common Names in Dutch:

Glad Vingergras

Common Names in English:

Small Crabgrass, Smooth Crab Grass, Smooth Crabgrass, Smooth Fingergrass

Common Names in Estonian:

Liiv-Paelhirss

Common Names in Finnish:

Nauhaverihirssi

Common Names in French:

Digitaire Filiforme, Digitaire Ischème (Switzerland)

Common Names in German:

Faden-Fingerhirse, Kahle Fingerhirse, Niederliegende Fingerhirse (Switzerland)

Common Names in Italian:

Sanguinella Glabra, Sanguinella Sottile (Switzerland)

Common Names in Polish:

Palusznik Nitkowaty

Common Names in Spanish:

Garrachuelo Pequeño

Common Names in Swedish:

Fingerhirs

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 ischaemum

Annual , whole plant often purple-tinged. Culms loosely tufted , erect or ascending , 15-40 cm tall. Leaf sheaths loose , usually keeled , glabrous or pilose ; leaf blades linear-lanceolate, 5-12 × 0.4-0.8 cm, ± pilose, base subrounded, apex acuminate; ligule ca. 0.6 mm. Inflorescence digitate or on a short axis; racemes 2-4, divaricate , 2-9 cm; spikelets ternate ; rachis ribbonlike, winged , 0.8-1.1 mm broad, midrib white, rounded or triquetrous , narrower than the green or purple wings , margins serrulate ; pedicels angular, scabrous , tips discoid . Spikelets elliptic , 2-2.2 mm, pilose with verrucose hairs , some with curled tips; lower glume absent or a tiny hyaline rim ; upper glume as long as spikelet or slightly shorter, 3-5-veined, intervein spaces and margins appressed-pilose; lower lemma as long as spikelet, 5-7-veined, interveins and margins appressed-pilose; upper lemma purplish brown to blackish at maturity. Fl. and fr. Jun-Nov. 2n = 36. [source]

Digitaria ischaemum is very close to D. violascens, but has a slightly stouter habit with broader leaves, a few short, widely spreading racemes, and larger, plumper spikelets. It also has a more temperate distribution. [source]

Digitaria ischaemum, D. fauriei, D. longiflora, and D. violascens belong to a group of Digitaria known as the Verrucipilae because of their warty spikelet hairs. A compound microscope is required to see this, but the hairs have a beadlike appearance under moderate magnification. These spikelet hairs also have curled tips in D. ischaemum (and sometimes in D. violascens), which led to the hairs being described as capitate or clavate in the past. [source]

Habitat

Open grassy places.[2].

Typically found at an altitude of 0 to 2,793 meters (0 to 9,163 feet).[3]

Taxonomy

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Synonyms

D. humi-fusa Persoon • D. ischaemum asiatica (Ohwi) Tzvelev • D. ischaemum var. asiatica Ohwi • Digitaria asiatica (Ohwi) Tzvelev • Digitaria ischaemum var. mississippiensis (Gattinger) Fern. • Panicum humifusum (Persoon) Kunth • Panicum ischaemum Schreb. • Panicum ischaemum Schreber in Schweigger • Paspalum humifusum (Persoon) Poiret • Spec. Fl. Erlang. 16. 1804 • Syntheris-ma humifusa (Persoon) Rydberg. • Syntherisma ischaemum (Schreb.) Nash

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 February 28, 2008:

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 ischaemum". in Flora of China Vol. 22 Page 540, 541, 546, 547. Missouri Botanical Garden Press. Online at EFloras.org. [back]
  3. Mean = 237.330 meters (778.642 feet), Standard Deviation = 244.980 based on 3,445 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/15/2012