Persicaria arifolia |
Persicaria |
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halberd-leaf smartweed, halberd-leaf tearthumb, renouée à feuilles d'arum |
knotweed, smartweed, tearthumb |
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Habit | Plants annual, 2–15 dm; roots also often arising from proximal nodes. | Herbs, perennial or annual (sometimes suffrutescent in P. wallichii); taprooted or fibrous-rooted; sometimes rhizomatous or stoloniferous. | ||||||||||||||||
Stems | scandent, ribbed, glabrous; prickles 0.5–1 mm. |
erect or, sometimes, prostrate or scandent, simple or branched, glabrous or pubescent, rarely with recurved prickles. |
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Leaves | ocrea tan or brownish, cylindric, 8–15 mm, chartaceous, base inflated or not, with prickles, margins oblique, ciliate with bristles 0.5–2.5 mm, surface glabrous or appressed- to spreading-pubescent; petiole 1–7 cm; blade broadly hastate to hastate-cordate or triangular, (2–)6.5–13(–18) × (1–)6–11(–16) cm, base truncate to truncate-cordate, margins broadly hastate with lobes divergent, ciliate, sometimes also retrorsely prickly, apex acuminate, faces appressed-pubescent or, rarely, glabrous adaxially, stellate-pubescent or, rarely, glabrous abaxially, major veins often bearing prickles. |
deciduous, mostly cauline, alternate, petiolate or sessile; ocrea persistent or disintegrating with age and deciduous entirely or distally, usually tan, brown, or reddish, chartaceous or partially to entirely foliaceous, rarely coriaceous proximally and chartaceous distally, glabrous or scabrous to variously pubescent, never 2-lobed distally; blade lanceolate or ovate to hastate or sagittate, margins entire or, rarely, hastately lobed. |
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Inflorescences | capitate or paniclelike, uninterrupted, 5–12 × 3–8 mm; peduncle 10–80 mm, retrorsely prickly proximally, stellate-pubescent and stipitate-glandular distally, glands red or pink; ocreolae usually overlapping, sometimes not overlapping proximally, margins eciliate or ciliate with bristles to 0.5 mm. |
terminal or terminal and axillary, spikelike, paniclelike, or capitate; peduncle present. |
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Pedicels | mostly ascending, 2–3 mm. |
present or absent. |
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Flowers | 2–4 per ocreate fascicle; perianth pink or red, often whitish green proximally, glabrous, accrescent, not becoming blue and fleshy in fruit; tepals 4, connate 1/3–1/2 their length, broadly elliptic, 5–6 mm, apex acute to obtuse; stamens (6–)8, filaments distinct, free; anthers pink, elliptic; styles 2, distinct. |
bisexual (often functionally unisexual in P. amphibia and P. hydropiperoides), 1–14 per ocreate fascicle, base not stipelike; perianth white, greenish white, roseate, red, or purple, campanulate or urceolate, rarely rotate, rarely becoming fleshy in fruit, glabrous, sometimes glandular-punctate, accrescent or nonaccrescent; tepals 4–5, connate 1/4–2/3 their lengths (less than 1/5 their lengths in P. wallichii), petaloid, dimorphic, outer larger than inner; stamens 5–8, filaments distinct or connate basally, outer ones sometimes adnate to perianth tube, glabrous; anthers yellow, pink, or red, elliptic to ovate; styles 2–3, erect to spreading or reflexed, distinct or connate; stigmas capitate. |
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Achenes | included, dark brown to black, biconvex, 3.5–6 × 3–4 mm, shiny, smooth. |
included or exserted, brown or dark brown to black, not winged, discoid, biconvex, 2–3-gonous, or spheroidal, glabrous. |
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Seeds | embryo curved. |
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x | = 10, 11, 12. |
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Persicaria arifolia |
Persicaria |
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Phenology | Flowering Jul–Oct. | |||||||||||||||||
Habitat | Shaded swamps, ponds, tidal marshes along rivers, wet ravines in forests | |||||||||||||||||
Elevation | 0-600 m (0-2000 ft) | |||||||||||||||||
Distribution |
CT; DC; DE; GA; IL; IN; KY; LA; MA; MD; ME; MI; MN; MO; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WA; WI; WV; NB; NS; ON; PE; QC
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Nearly worldwide |
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Discussion | Species ca. 100 (26 in the flora). Opinions vary widely about the circumscription and infrageneric classification of Persicaria. The concept employed here generally follows L.-P. Ronse Decraene et al. (2000) and K. Haraldson (1978), with five sections recognized in the flora. Aconogonon and Bistorta, which often are included in Persicaria or in Polygonum in the broad sense, are treated here as separate genera. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key | Key to the Sections of Persicaria
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Source | FNA vol. 5, p. 577. | FNA vol. 5, p. 574. | ||||||||||||||||
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon | Polygonaceae > subfam. Polygonoideae | ||||||||||||||||
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Subordinate taxa | ||||||||||||||||||
Synonyms | Polygonum arifolium, Polygonum arifolium var. lentiforme, Polygonum arifolium var. pubescens, Polygonum sagittatum var. pubescens, Tracaulon arifolium, Truellum arifolium | Polygonum unranked P. | ||||||||||||||||
Name authority | (Linnaeus) Haraldson: Acta Univ. Upsal., Symb. Bot. Upsal. 22: 72. (1978) | (Linnaeus) Miller: Gard. Dict. Abr. ed. 4, vol. 3. (1754) | ||||||||||||||||
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