Persicaria hydropiperoides |
Persicaria longiseta |
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false water pepper, false water-pepper smartweed, mild waterpepper, renouée faux-poivre-d'eau, swamp smartweed, water-pepper |
bristly lady's-thumb, oriental lady's thumb, oriental lady's-thumb smartweed |
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Habit | Plants perennial, 1.5–10 dm; roots also often arising from proximal nodes; rhizomes often present. | Plants annual, 3–8 dm; roots also often arising from proximal nodes; rhizomes and stolons absent. |
Stems | decumbent to ascending, usually branched, without noticeable ribs, glabrous or obscurely strigose distally. |
decumbent to ascending, branched, without noticeable ribs, glabrous. |
Leaves | ocrea brown, cylindric, 5–23 mm, chartaceous, base inflated, margins truncate, ciliate with bristles (2–)4–10 mm, surface glabrous or strigose, not glandular-punctate; petiole 0.2–2 cm, glabrous or strigose; blade without dark triangular or lunate blotch adaxially, broadly lanceolate to linear-lanceolate, 5–25 × 0.4–3.7 cm, base tapered or acute, margins antrorsely appressed-pubescent, apex acuminate, faces glabrous or appressed-pubescent along midveins and sometimes on faces, usually punctate abaxially. |
ocrea hyaline to brownish, cylindric, 5–12 mm, chartaceous, base sometimes inflated, margins truncate, ciliate with bristles 4–12 mm, surface glabrous or strigose, not glandular-punctate; petiole 0.1–0.3(–0.6) cm, glabrous, leaves sometimes sessile; blade without dark triangular or lunate blotch adaxially, ovate-lanceolate to linear-lanceolate, 2–8 × 1–3 cm, base tapering to cuneate, margins antrorsely strigose, apex acute to acuminate, faces glabrous or sparingly strigose along veins abaxially, glabrous or strigose along midvein and margins adaxially, not glandular-punctate. |
Inflorescences | terminal, sometimes also axillary, erect, uninterrupted or interrupted proximally, 30–80 × 2–5 mm; peduncle 10–30 mm, glabrous or strigose; ocreolae overlapping distally, often not overlapping proximally, margins ciliate with bristles to 2(–3) mm. |
terminal, sometimes also axillary, erect, uninterrupted, 10–40(–80) × 3–7 mm; peduncle 10–50 mm, glabrous; ocreolae overlapping, margins ciliate with bristles (0.5–)1–4(–6) mm. |
Pedicels | ascending, 1–1.5 mm. |
ascending, 1–2 mm. |
Flowers | bisexual or unisexual and staminate, 2–6 per ocreate fascicle, homostylous; perianth roseate proximally, roseate, white, or greenish white distally, not glandular-punctate or sometimes glandular-punctate with punctae on tubes and inner tepals, scarcely accrescent; tepals 5, connate ca. 1/3–1/2 their length, obovate, 2.5–4 mm in bisexual flowers, 1.5–2.5 mm in staminate flowers, veins prominent or not, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 8, included or exserted in staminate flowers; anthers pink or red, elliptic to ovate; styles 3, connate near middle. |
1–5 per ocreate fascicle, homostylous; perianth pinkish green proximally, roseate distally, glabrous, not glandular-punctate, scarcely accrescent; tepals 5, connate ca. 1/3 their length, obovate, 2.2–2.8 mm, veins not prominent, not anchor-shaped, margins entire, apex obtuse to rounded; stamens 5, included; anthers yellow, elliptic to ovate; styles 3, connate proximally. |
Achenes | included or apex exserted, brown to brownish black or black, 3-gonous, 1.5–3 × 1–2.3 mm, shiny, smooth. |
included, dark brown to black, 3-gonous, 1.6–2.3 × 1.1–1.6 mm, shiny, smooth. |
Persicaria hydropiperoides |
Persicaria longiseta |
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Phenology | Flowering Jun–Nov. | Flowering May–Oct. |
Habitat | Wet banks and clearings, shallow water, marshes, moist prairies, ditches | Floodplain forests and woodlands, shorelines of ponds, moist roadsides, waste places |
Elevation | 0-1500 m (0-4900 ft) | 0-300 m (0-1000 ft) |
Distribution |
AK; AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; VA; VT; WA; WI; WV; BC; NB; NS; ON; QC; Mexico; Central America; South America
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AL; CT; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NJ; NY; OH; PA; SC; TN; TX; VA; VT; WI; WV; BC; NB; ON; e Asia [Introduced in North America; introduced also in Europe]
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Discussion | The extreme variability in Persicaria hydropiperoides is reflected in its extensive synonymy. Among the segregates most often recognized in floras and checklists is P. opelousana, which C. B. McDonald (1980) showed to be broadly sympatric and highly interfertile with P. hydropiperoides. Consistent with this conclusion, R. S. Mitchell (1971) found that P. hydropiperoides and P. opelousana are unique among native North American smartweeds in consistently possessing multicellular plate-glands on the abaxial surface of their leaves. Such glands also are found on P. maculosa, an introduced European species. Herbarium specimens of Persicaria hydropiperoides sometimes are misidentified as P. maculosa, especially when the roots are missing. The former species may be distinguished reliably by its achenes all trigonous (trigonous and biconvex achenes are mixed in the inflorescences of P. maculosa) and bristles on the margins of the ocreae that average longer. M. L. Fernald (1922c) reported hybrids with P. robustior from Nova Scotia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Persicaria longiseta is morphologically similar to another Asian species, P. posumbu (Buchanan-Hamilton ex D. Don) H. Gross (= P. caespitosa). Its spread in the United States since its introduction near Philadelphia in 1910 was summarized by A. K. Paterson (2000). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 585. | FNA vol. 5, p. 592. |
Parent taxa | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria | Polygonaceae > subfam. Polygonoideae > Persicaria > sect. Persicaria |
Sibling taxa | ||
Synonyms | Polygonum hydropiperoides, P. opelousana, P. paludicola, Polygonum hydropiperoides var. adenocalyx, Polygonum hydropiperoides var. asperifolium, Polygonum hydropiperoides var. breviciliatum, Polygonum hydropiperoides var. bushianum, Polygonum hydropiperoides var. digitatum, Polygonum hydropiperoides var. opelousanum, Polygonum hydropiperoides var. psilostachyum, Polygonum opelousanum, Polygonum opelousanum var. adenocalyx | Polygonum longisetum, P. caespitosa var. longiseta, Polygonum caespitosum var. longisetum |
Name authority | (Michaux) Small: Fl. S.E. U.S., 378. (1903) | (Bruijn) Kitagawa: Rep. Inst. Sci. Res. Manchoukuo 1: 322. (1937) |
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