Persicaria sagittata |
Persicaria capitata |
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arrow-leaf knotweed, arrow-leaf tearthumb, arrow-vine, renouée sagittée |
Himalayan smartweed, Japanese knotweed, pink bubble persicaria, pink-head knotweed, pink-head persicaria, pinkhead smartweed |
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Habit | Plants annual, 3–20 dm; roots also often arising from proximal nodes. | Plants annual or perennial, 0.5–5 dm; roots also often arising from proximal nodes. |
Stems | scandent, ribbed, glabrous; prickles 1–1.5 mm. |
prostrate, glabrous or glandular-pubescent. |
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. |
ocrea brown or reddish brown, cylindric to funnelform, 5–12 mm, chartaceous, base inflated or not, margins oblique, eciliate or ciliate with bristles to 1.5 mm, surface lanate, sometimes also glandular-pubescent; petiole 2–5 mm, winged distally; blade ovate to elliptic, 1.5–4(–6) × 0.6–2.5(–3.3) cm, base cuneate or tapering, margins ciliate with reddish, multicellular hairs, apex acute, faces glandular-pubescent abaxially and adaxially, not glandular-punctate. |
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. |
terminal, 5–20 × 7-18 mm; peduncle 10–40 mm, glabrous or stipitate-glandular in distal 1/5; ocreolae overlapping, margins eciliate. |
Pedicels | mostly ascending, 1–1.5 mm. |
spreading, 0.5–1 mm. |
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. |
1–5 per ocreate fascicle; perianth greenish white proximally, pinkish distally, urceolate, glabrous, nonaccrescent; tepals 5, elliptic, 2–3 mm, apex acute to obtuse; stamens 8, filaments distinct, free; anthers pink to red, elliptic; styles 3, connate to middle or distally. |
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. |
included, reddish brown to brownish black, 3-gonous, 1.5–2.2 × 1–1.5 mm, shiny, smooth or minutely punctate. |
2n | = 40. |
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Persicaria sagittata |
Persicaria capitata |
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Phenology | Flowering Jun–Oct. | Flowering Jun–Sep. |
Habitat | Moist shaded sites, meadows, pastures, fens, swamps, shorelines of ponds and streams | Disturbed, urban places |
Elevation | 0-1000 m (0-3300 ft) | 0-500 m (0-1600 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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CA; LA; OR; Asia (Bhutan, w China, n India, Nepal) [Introduced in North America; introduced also in the Pacific Islands (Hawaii)]
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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.) |
Persicaria capitata is planted as a garden groundcover. It escapes infrequently in the flora area; once established outside of cultivation it can be difficult to eradicate. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 577. | FNA vol. 5, p. 579. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Echinocaulon | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Cephalophilon |
Sibling taxa | ||
Synonyms | Polygonum sagittatum, Polygonum sagittatum var. gracilentum, Tracaulon sagittatum, Truellum sagittatum | Polygonum capitatum |
Name authority | (Linnaeus) H. Gross: Beih. Bot. Centralbl. 37(2): 113. (1919) | (Buchanan-Hamilton ex D. Don) H. Gross: Bot. Jahrb. Syst. 49: 277. (1913) |
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