Persicaria wallichii |
Persicaria |
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garden knotweed, garden smartweed, Himalayan knotweed, Kashmir plume |
knotweed, smartweed, tearthumb |
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Habit | Herbs, perennial or annual (sometimes suffrutescent in P. wallichii); taprooted or fibrous-rooted; sometimes rhizomatous or stoloniferous. | |||||||||||||||||
Stems | erect or, sometimes, prostrate or scandent, simple or branched, glabrous or pubescent, rarely with recurved prickles. |
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Leaves | 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 | terminal or terminal and axillary, spikelike, paniclelike, or capitate; peduncle present. |
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Pedicels | present or absent. |
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Flowers | 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 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 wallichii |
Persicaria |
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Distribution |
CA; MA; OR; BC; Asia
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Nearly worldwide |
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Discussion | Varieties 2 (1 in the flora). Persicaria wallichii is an ornamental that escapes infrequently in the flora area. A population in Nova Scotia apparently was ephemeral. Plants with leaf blades sparsely to densely pubescent abaxially and pedicels glabrous are var. wallichii, to which naturalized North American plants appear to be referable. Plants with leaf blades brownish-tomentose abaxially and pedicels usually pubescent are var. tomentosa S. P. Hong, which may be in cultivation in North America. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. 581. | FNA vol. 5, p. 574. | ||||||||||||||||
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Rubrivena | Polygonaceae > subfam. Polygonoideae | ||||||||||||||||
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Synonyms | Polygonum polystachyum, Aconogonon polystachyum, Pleuropteropyrum polystachyum, Reynoutria polystachya, Rubrivena polystachya | Polygonum unranked P. | ||||||||||||||||
Name authority | Greuter & Burdet: Willdenowia 19: 41. (1989) | (Linnaeus) Miller: Gard. Dict. Abr. ed. 4, vol. 3. (1754) | ||||||||||||||||
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