Persicaria bicornis |
Persicaria arifolia |
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pink smartweed |
halberd-leaf smartweed, halberd-leaf tearthumb, renouée à feuilles d'arum |
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Habit | Plants annual, 2–18 dm; roots also rarely arising from basal nodes; rhizomes and stolons absent. | Plants annual, 2–15 dm; roots also often arising from proximal nodes. |
Stems | ascending to erect, rarely decumbent, branched, ribbed, glabrous or appressed-pubescent to spreading-pubescent distally, stipitate-glandular or, rarely, without stipitate-glands. |
scandent, ribbed, glabrous; prickles 0.5–1 mm. |
Leaves | ocrea brownish, cylindric, 6–20 mm, chartaceous, base inflated, margins truncate, eciliate or ciliate with bristles to 1 mm, surface glabrous or scabrous proximally, eglandular; petiole 0.1–1.5(–2.3) cm, glabrous or appressed-pubescent; blade sometimes with dark triangular or lunate blotch adaxially, linear-lanceolate to ovate-lanceolate, 2.3–13(–18) × (0.4–)1–2.3 cm, base tapered to cuneate, margins antrorsely scabrous, apex acute to acuminate, faces glabrous or appressed-pubescent along midveins, glandular-punctate abaxially. |
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. |
Inflorescences | terminal and axillary, erect, uninterrupted, 8–60 × 10–18 mm; peduncle 8–60(–70) mm, glabrous or pubescent, usually stipitate-glandular; ocreolae overlapping, margins eciliate or ciliate with bristles to 0.8 mm. |
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. |
Pedicels | ascending, 1.5–5 mm. |
mostly ascending, 2–3 mm. |
Flowers | 2–11 per ocreate fascicle, heterostylous; perianth pink, glabrous, not glandular-punctate, accrescent; tepals 5, connate ca. 1/4–1/3 their length, obovate to elliptic, 3–4.6 mm, veins prominent, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 6–8, included or exserted; anthers pink or red, elliptic; styles 2(–3), included or exserted, connate at bases. |
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. |
Achenes | included or apex exserted, brownish black to black, discoid or, rarely, 3-gonous, 1 side usually slightly concave and other with central hump, (2–)2.2–2.9 × 2–2.8(–3) mm, shiny, smooth. |
included, dark brown to black, biconvex, 3.5–6 × 3–4 mm, shiny, smooth. |
Persicaria bicornis |
Persicaria arifolia |
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Phenology | Flowering Jun–Oct. | Flowering Jul–Oct. |
Habitat | Moist, disturbed places, permanent and ephemeral wetlands, ditches, cultivated fields, shorelines of ponds and reservoirs | Shaded swamps, ponds, tidal marshes along rivers, wet ravines in forests |
Elevation | 50-1600 m (200-5200 ft) | 0-600 m (0-2000 ft) |
Distribution |
AR; CO; IA; IL; KS; LA; MO; NE; NM; OK; SD; TX; WY
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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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Discussion | Persicaria bicornis is a characteristic smartweed of permanent and ephemeral wetlands and moist, disturbed sites in the Great Plains. It often has been included in P. pensylvanica but can be distinguished readily by its heterostylous flowers. The achenes, which usually bear an obscure or prominent hump in the center of one face, also are diagnostic. This hump often ruptures the side of the perianth on fruiting herbarium specimens. Persicaria bicornis also has leaf blades that are on average narrower than are those of P. pensylvanica, and populations exhibit less variation in perianth color. As in P. pensylvanica, flowers with three styles and trigonous achenes are produced very rarely. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 5, p. 589. | FNA vol. 5, p. 577. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon |
Sibling taxa | ||
Synonyms | Polygonum bicorne, P. longistyla, Polygonum longistylum | Polygonum arifolium, Polygonum arifolium var. lentiforme, Polygonum arifolium var. pubescens, Polygonum sagittatum var. pubescens, Tracaulon arifolium, Truellum arifolium |
Name authority | (Rafinesque) Nieuwland: Amer. Midl. Naturalist 3: 201. (1914) | (Linnaeus) Haraldson: Acta Univ. Upsal., Symb. Bot. Upsal. 22: 72. (1978) |
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