Persicaria hydropiperoides |
Persicaria glabra |
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false water pepper, false water-pepper smartweed, mild waterpepper, renouée faux-poivre-d'eau, swamp smartweed, water-pepper |
denseflower knotweed, smooth smartweed |
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Habit | Plants perennial, 1.5–10 dm; roots also often arising from proximal nodes; rhizomes often present. | Plants perennial, 3–15 dm; roots also often arising from proximal nodes; rhizomes present. |
Stems | decumbent to ascending, usually branched, without noticeable ribs, glabrous or obscurely strigose distally. |
decumbent to erect, usually branched distally, without noticeable ribs, glabrous or, rarely, pubescent distally, sometimes glandular-punctate. |
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 light brown, cylindric, 12–23 mm, chartaceous, base inflated, margins truncate, eciliate, surface glabrous, usually obscurely glandular-punctate; petiole 0.2–2 cm, scabrous; blade without dark triangular or lunate blotch adaxially, lanceolate, (10–)15–30 × (1.5–)2–5.4 cm, base tapered, margins glabrous or antrorsely strigose, apex acute to acuminate, faces glabrous or scabrous along midveins, sometimes 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. |
mostly terminal, sometimes also axillary, erect to slightly nodding, usually uninterrupted, 30–100 × 5–9 mm; peduncle 10–50 mm, glabrous or scabrid, glandular-punctate; ocreolae usually overlapping, margins eciliate. |
Pedicels | ascending, 1–1.5 mm. |
erect to spreading, 2–5 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–)3–8 per ocreate fascicle, homostylous; perianth greenish white to white or pink, glabrous, not glandular-puncate or glandular-punctate with punctae ± uniformly distributed, scarcely accrescent; tepals 5, connate ca. 1/3 their length, obovate, 3–3.6 mm, veins not prominent, not anchor shaped, margins entire, apex obtuse to rounded; stamens 5–7, included; anthers pink or red, ovate; styles 2, 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 brownish black, biconvex, 2–2.2 × 1.3–1.6 mm, shiny, smooth. |
Persicaria hydropiperoides |
Persicaria glabra |
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Phenology | Flowering Jun–Nov. | Flowering Aug–Nov. |
Habitat | Wet banks and clearings, shallow water, marshes, moist prairies, ditches | Swamps, wet thickets, marshy shores, frequently in water, mostly on coastal plain of e North America |
Elevation | 0-1500 m (0-4900 ft) | 0-300 |
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; AR; DE; FL; GA; KY; LA; MD; MO; MS; NC; NJ; SC; TN; TX; VA; Central America; South America; Asia; ne Africa; Pacific Islands (Hawaii, Philippines)
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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.) |
American plants here included in Persicaria glabra often have been treated as distinct and called P. densiflora. The morphological differences between them and Asian and Pacific P. glabra are minor. Regional tendencies exist but do not appear sufficient to warrant separation of the species (K. L. Wilson 1990b). An infusion made from pounded whole plants was used by the Hawaiians as a blood medicine (D. E. Moerman 1998). Persicaria portoricensis Small and Polygonum portoricense Bertero ex Small are superfluous and illegitimate names that pertain here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 585. | FNA vol. 5, p. 586. |
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 glabrum, P. densiflora, Polygonum densiflorum |
Name authority | (Michaux) Small: Fl. S.E. U.S., 378. (1903) | (Willdenow) M. Gómez: Anales Inst. Segunda Enseñ. 2: 278. (1896) |
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