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Stalked Bur Grass

Tragus racemosus (L.) All.

Comprehensive Description

provided by North American Flora
Nazia racemosa (I,.) Kuntze, Rev. Gen. 780. 1891
Cenchrus racemosus 'L,. Sp. PI. 1049. 1753. Phalaris muricata Forsk. Fl. Aegypt.-Arab. 202. 1775. Tragus racemosus All. Fl. Fed. 2 : 241. 1785. Tragus m.uricatus Moench, Meth. 53. 1794. Lappago racemosa Willd. Sp. PI. 1 : 484. 1798.
Stems up to 4 dm. tall, often rooting at the lower nodes and there sending up tufts of erect branches; leaf-sheaths smooth and glabrous; blades up to 6 cm. long, usually less than 4 cm., 2-4 mm. wide, flat, ciliate on the margins, otherwise glabrous; inflorescence 2-8 cm. long, often included at the base; spikelets 4—4.5 mm. long, the spines with the somewhat swollen opaque base shorter than the translucent apex, the longer ones often 1 mm. in length.
Type locality : Southern Europe.
Distribution : Occasionally introduced about cities or as a ballast waif ; native of the warm temperate and tropical regions of the Old World.
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bibliographic citation
George Valentine Nash. 1912. (POALES); POACEAE (pars). North American flora. vol 17(2). New York Botanical Garden, New York, NY
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Physical Description

provided by USDA PLANTS text
Annuals, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2 -ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Ligule present, Ligule a fringe of hairs, Inflorescence terminal, Inflorescence a dense slender spike-like panicle or raceme, branches contracted, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence spike linear or cylindric, several times longer than wide, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets sessile or subsessile, Spikelets dorsally compressed or terete, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets paired at ra chis nodes, Spikelets bisexual, Spikelets disarticulating below the glumes, Spikelets falling with parts of disarticulating rachis or pedicel, 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, Glumes and spikelets tuberculate, warty, or spiny, Glume surface hairy, villous or pilose, Glumes 4-7 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma 3 nerved, Lemma body or surface hairy, Lemma apex acute or acuminate, Lemma awnless, Lemma margins thin, lying flat, Lemma straight, Lemma surface pilose, setose or bristly, Palea present, well developed, Palea membranous, hyaline, Palea about equal to lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear, Tragus racemosus Annuals, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Ligule present, Ligule a fringe of hairs, Inflorescence terminal, Inflorescence a dense slender spike-like panicle or raceme, branches contracted, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, I nflorescence spike linear or cylindric, several times longer than wide, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence branches more than 10 to numerous, Peduncle or rachis scabrous or pubescent, often with long hairs, Flowers bisexual, Spikelets pedicellate, Spikelets sessile or subsessile, Spikelets dorsally compressed or terete, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets paired at rachis nodes, Spikelets bisexual, Spikelets disarticulating below the glumes, Spikelets falling with parts of disarticulating rachis or pedicel, Rachilla or pedicel hairy, 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, Glumes and spikelets tuberculate, warty, or spiny, Glume surface hairy, villous or pilose, Glumes 4-7 nerved, Lemmas thin, chartaceous, hyaline, cartilaginou s, or membranous, Lemma 3 nerved, Lemma body or surface hairy, Lemma apex acute or acuminate, Lemma awnless, Lemma margins thin, lying flat, Lemma straight, Lemma surface pilose, setose or bristly, Palea present, well developed, Palea membranous, hyaline, Palea about equal to lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.
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Dr. David Bogler
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Tragus racemosus

provided by wikipedia EN

Tragus racemosus, commonly referred to as stalked bur grass,[1] European bur grass,[2] or large carrot seed grass,[3] is a species of grass native to Europe.[4] It is often confused with a similar plant of the same genus, Tragus berteronianus.[5] It is a monocot and is considered a weed in many countries and is a relatively uncommon seed contaminant.[2]

Description

Mature Tragus racemosus plants are typically 0.5-1.5 ft. (15.24-45.72 cm) tall with clustered stems.

Leaves are mostly cauline and arranged in a distichous manner. They are typically 1.5-4 mm long and do not have auricles.[6] There is a distinct separation between the leaf blade and the leaf sheath.

Leaf blades are linear and filiform with parallel venation. They are typically 0.5-5.5 cm long and 1.5-4mm wide.[6] The surface of the leaf is mostly glabrous with ligules present.

Branches are typically 2.1-4.8 mm long, with 2-5 spikelets paired at rachis nodes. Flowers can be found attached to branches with racemouse inflorescence. They contain 3 yellow anthers between 0.6-0.8 mm[6][5] and 2 white stigmas.[7] Proximal spikelets are 3.8-6.6 mm, second spikelets are 2.3-6.6 mm, and the third and fourth spikelets are 0.8-4.2 mm.[6] Each spikelet contains one floret with smooth lemma. Each lemma contains 3 veins.

Unlike other members of the Tragus genus who have a chromosome count of 2n=20, Tragus racemosus has a chromosome count of 2n=40.

Tragus racemosus, along with other members in the Tragus species, utilizes C4 photosynthesis.[8]

Distribution and habitat

Tragus racemosus is native to Europe, Asia, and Africa. It has been specifically identified in Austria, Belgium, Bulgaria, Czechia, Germany, Hungary, Spain, and the United Kingdom.

Tragus racemosus is an introduced species to North and South America[4] and has been found in established populations in Arizona[9] where it grows in sandy soil. It can occasionally be found in New England. Accounts of Tragus racemosus on the Western coast of the United States have been in manmade or disturbed habitats such as dump sites or construction sites and have not resulted in established populations.[6] It has been reported in New Mexico and Texas, but these reports have since been contributed to confusion with a similar grass species of the same genus, Tragus berteronianus.[9]

Phenology

Tragus racemosus is an annual plant. As is common with other species that use C4 photosynthesis, it grows primarily in the hot and dry periods of the summer months.[8] In the northern hemisphere, it has been reported to flower in August and October. It has also been reported to produce fruit in August and October. It appears to have leaves from late July through early November.[2][10]

Uses

Because Tragus racemosus is a grass, it can be used to reduce soil erosion in areas where it is native to.[11]

Species of the Tragus genus, including Tragus racemosus, are not suitable grasses for grazing. If these plants are found in abundance, it could suggest overgrazing, in which the other grasses suitable for grazing are eaten, eliminating competition and allowing Tragus racemosus to grow in larger quantities.[1][12]

References

  1. ^ a b "Plants Profile for Tragus racemosus (stalked bur grass)". plants.usda.gov. Retrieved 2020-12-05.
  2. ^ a b c "Tragus racemosus (L.) All., European bur grass (Weeds)". Pl@ntNet. Retrieved 2020-12-10.
  3. ^ "Plants of the World Online | Kew Science". Plants of the World Online. Retrieved 2020-12-10.
  4. ^ a b "Tragus racemosus". www.cabi.org. Retrieved 2020-12-05.
  5. ^ a b "Tragus". Herbarium. Archived from the original on 2010-06-26. Retrieved 2020-12-05.
  6. ^ a b c d e "Tragus racemosus (stalked burgrass): Go Botany". gobotany.nativeplanttrust.org. Retrieved 2020-12-06.
  7. ^ "Grass genera of the world - Tragus Haller". www.delta-intkey.com. Retrieved 2020-12-11.
  8. ^ a b Kalapos, Tibor (January 1991). "C3 and C4 grasses of Hungary: environmental requirements, phenology and role in the vegetation". Abstracta Botanica – via ResearchGate.
  9. ^ a b Reeder, John R.; Reeder, Charlotte (1978). "Tragus racemosus in Arizona". Madroño. 25 (2): 107–108. ISSN 0024-9637. JSTOR 41424145.
  10. ^ "European Bur-Grass (Tragus racemosus)". iNaturalist. Retrieved 2020-12-10.
  11. ^ "StackPath". www.gardeningknowhow.com. Retrieved 2020-12-15.
  12. ^ "Flora of Botswana: Species information: Tragus berteronianus". www.botswanaflora.com. Retrieved 2020-12-15.
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Tragus racemosus: Brief Summary

provided by wikipedia EN

Tragus racemosus, commonly referred to as stalked bur grass, European bur grass, or large carrot seed grass, is a species of grass native to Europe. It is often confused with a similar plant of the same genus, Tragus berteronianus. It is a monocot and is considered a weed in many countries and is a relatively uncommon seed contaminant.

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