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Species
Polygonum hydropiper L. (1753)
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Erect, 30-45 (-50) cm high with tufted roots branched from base or above, or sometime simple, annual to perennial herb. Stem glabrous, brown, sometimes shining. Leaves 1.5-8 (-10) x 0.4-1.5 (-2) cm, linear lanceolate to lanceolate, acuminate, margin ciliate, surface glabrous or scabrous or slightly pubescent beneath on the midrib and reddish punctate gland-dotted on both surfaces, petiole 0.2-0.4 cm long. Ochreae 0.25-1.5 (-2.0) cm long, glabrous, ciliae at the mouth of ochrea 1-4 mm long. Inflorescence 3-7 cm long, lax, flowers ± distant, erect, not drooping pedunculate raceme; peduncles 1.0-6.5 cm long. Flowers 1.0-2.0 mm across, pedicellate; pedicel 0.5-1.25 mm long. Ochreolae 1.0-2.0 mm long, ovate, dentate-entire, gland-dotted. Tepals 5, pink, 1.0-3.0 x 0.75-1.5 mm, obovate, obtuse, red gland-dotted. Stamens 6, filaments long, unequal. Ovary 0.5-1.5 x 0.5-0.75 mm, trigonous, elliptic with 3 or sometimes 2 styles united in the upper half, then free; stigma capitate. Nuts 2.5-3.5 (-4) x 1.5-2.0 mm, mostly trigonous, sometimes biconvex within the same raceme, dark brownish, pubescent.
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Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=242100096 |
Flowering May-Nov.
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242100096 |
Herbs annual. Stems erect, 40-70 cm tall, much branched, glabrous, dilated at nodes. Leaves with peppery taste; petiole 4-8 mm; leaf blade lanceolate or elliptic-lanceolate, 4-8 × 0.5-25 cm, both surfaces glabrous, densely brown punctate, sometimes appressed hispidulous along midvein, base cuneate, margin ciliate, apex acuminate; cleistogamous flowers present in many leaf axils; ocrea tubular, 1-1.5 cm, membranous, sparsely appressed hispidulous, apex truncate, shortly ciliate. Inflorescence terminal or axillary, spicate, pendulous, interrupted below, usually lax, 3-8 cm, slender; bracts green, funnel-shaped, 2-3 mm, margin membranous, sparsely shortly ciliate, each 3-5-flowered. Pedicels longer than bracts. Perianth greenish, white or pink above, 5(or 4)-parted, brownish pellucid glandular punctate; tepals elliptic, 3-3.5 mm. Stamens 6, rarely 8, included. Styles 2 or 3. Achenes included in persistent perianth, black-brown, opaque, ovoid, biconvex or trigonous, 2-3 mm, densely small pitted. Fl. May-Sep, fr. Jun-Oct. 2n = 18-22.
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200006723 |
Fl. Per.: April-September.
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=242100096 |
This is one of the many weedy smartweeds in Illinois, which can be difficult to identify. Waterpepper can be distinguished from other smartweeds primarily by its racemes of flowers, which have the following key characteristics
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | Copyright © 2002-2014 by Dr. John Hilty |
Source | http://www.illinoiswildflowers.info/weeds/plants/waterpepper.htm |
"Stout herbs, procumbent below. Leaves subsessile, 3-7 x 1-2.2 cm, linear-lanceolate, base attenuate, apex acuminate, gland-dotted; ocrea to 1.5 cm long, tubular, glabrous, mouth with a few slender bristles. Racemes to 7 cm long, slender, lax, drooping. Bracts ovate, acute, gland-dotted. Perianth white with pink shades, gland-dotted; lobes 5, c. 2 mm long, ovate-obtuse. Stamens 5. Nuts biconvex."
Compounds deter insect feeding: water smartweed
Polygodial compounds from water smartweed deter insect feeding by blocking the effects of glucose and sucrose on insect taste receptors.
"Polygodial, a compound in Polygonum hydropiper (water smartweed) is among the most potent deterrents to insect feeding known.
"The deterrent effect appears to be a direct result of the action of polygodial on taste receptors. In lepidopteran larvae, polygodial and other drimane dialdehydes block the stimulatory effects of glucose and sucrose on chemosensory receptor cells found on the mouthparts (Frazier, 1986; Jansen and de Groot, 1991)." (Jansen & de Groot 1991)
Learn more about this functional adaptation.
- Jansen BJ; de Groot A. 1991. The occurrence and biological activity of drimane sesquiterpenoids. Nat Prod Rep. 8(3): 309-18.
- Zapata N; Vargas M; Medina P; Viñuela E; Rodriguez B; Fereres A. 2010. The activity of a selected extract of Drimys winteri bark and polygodial on settling and probing behavior of the lettuce aphid Nasonovia ribisnigri. Phytoparasitica. 38(2): 191-199.
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | (c) 2008-2009 The Biomimicry Institute |
Source | http://www.asknature.org/strategy/09971588e8da6f11a41c2ff597121f6f |
This introduced or adventive plant is a summer annual about 1-2' tall, branching occasionally. It has a tendency to sprawl and lean on adjacent plants for support. The hairless stems are green or red (often the latter). The alternate leaves are up to 3½" long ad ¾" across. They are lanceolate, smooth along the margins, and usually hairless. Their upper surface is often olive-green. Each leaf has a short petiole; the base of this petiole has a membranous sheath (an ocrea) that wraps around the stem. This sheath has a few bristly hairs along its upper rim. The sheaths of adjacent leaves on each stem are about 1-2" apart.
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | Copyright © 2002-2014 by Dr. John Hilty |
Source | http://www.illinoiswildflowers.info/weeds/plants/waterpepper.htm |
Polygonum hydropiper Linnaeus, Sp. Pl. 1: 361. 1753; P. hydropiper var. projectum Stanford
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242100096 |