Persicaria sagittata |
Persicaria meisneriana |
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arrow-leaf knotweed, arrow-leaf tearthumb, arrow-vine, renouée sagittée |
Mexican tearthumb |
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Habit | Plants annual, 3–20 dm; roots also often arising from proximal nodes. | |
Stems | scandent, ribbed, glabrous; prickles 1–1.5 mm. |
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Leaves | ocrea brownish, cylindric, (3–)5–13 mm, chartaceous, base inflated or not, without prickles, margins oblique, glabrous or ciliate at tip with bristles 0.2–1 mm, surface glabrous; petiole 0.5–4 cm; blade broadly lanceolate to oblong, 2–8.5 × 1–3 cm, base sagittate to cordate, margins entire, ciliate or eciliate, apex obtuse to acute, faces glabrous or densely appressed-pubescent, usually with retrorse prickles along midvein abaxially. |
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Inflorescences | capitate or paniclelike, uninterrupted, 5–15 × 4–10 mm; peduncle 10–80 mm, usually glabrous, sometimes with retrorse prickles proximally; ocreolae overlapping, margins eciliate. |
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Pedicels | mostly ascending, 1–1.5 mm. |
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Flowers | 2–3 per ocreate fascicle; perianth white or greenish white, often tinged pink or red, sometimes entirely pink, glabrous, accrescent, not becoming blue and fleshy in fruit; tepals 5, connate 1/3–1/2 their length, broadly elliptic, 3–5 mm, apex obtuse; stamens 8, filaments distinct, free; anthers pink, ovate; styles 3, connate to middle. |
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Achenes | included or styles exserted, light or dark brown to black, 3-gonous, 2.5–4 × 1.8–2.5 mm, dull to shiny, smooth to minutely punctate. |
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2n | = 40. |
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Persicaria sagittata |
Persicaria meisneriana |
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Phenology | Flowering Jun–Oct. | |
Habitat | Moist shaded sites, meadows, pastures, fens, swamps, shorelines of ponds and streams | |
Elevation | 0-1000 m (0-3300 ft) | |
Distribution |
AL; AR; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; MB; NB; NF; NS; ON; PE; QC; e Asia
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FL; GA; LA; SC; TX; Mexico; Central America; South America; West Indies; se Africa |
Discussion | Persicaria sagittata is an extremely variable species. Achene and leaf characters have been used by some authors to separate North American and Asian populations, but these characters show weak geographic variation (C. W. Park 1988). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (1 in the flora). Variety meisneriana has leaves with petioles 0.3–1 cm, blades prominently sagittate to hastate at bases, and ocreae usually moderately to densely pubescent. It is found only in South America (Argentina, Brazil, Paraguay). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 577. | FNA vol. 5, p. 578. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Polygonum sagittatum, Polygonum sagittatum var. gracilentum, Tracaulon sagittatum, Truellum sagittatum | Polygonum meisnerianum |
Name authority | (Linnaeus) H. Gross: Beih. Bot. Centralbl. 37(2): 113. (1919) | (Chamisso & Schlechtendal) M. Gómez: Anales Inst. Segunda Enseñ. 2: 278. (1896) |
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