Polygonum lapathifolium (Nodding smartweed)

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Polygonum lapathifolium L.

Nodding smartweed, pale smartweed, dock-leaved smartweed, curlytop knotweed

Nodding smartweed is a North American native. The genus Polygonum means “many knees”—a reference to the swollen, jointed sheaths the are found wherever leaf stems meet the vine.

Plants: 2–5′ (60–152 cm) high, usually upright, sometimes sprawling (the stems aren’t very strong), with green or deep red hairless stems.

Leaves: Alternate, typically lanceolate but variable in shape, fatter at the base and tapering to a sharp tip, 1¾–10 ⨉ ½–1¾″ (5–25 ⨉ 1.5–5 cm). Petioles are ⅜–¾″ (1–2 cm). Leaves have tiny, hooklike hairs that make them feel rough. They are not mottled. Where each leaf stem meets the main stem, there is a thick sheathlike joint (ocrea that is brownish, tubular, ½–1″ (1.5–3 cm) long, with few or no hairs.

Flowers: Greenish-white to pink, in columns about ¼–⅜″ (6.3–9.5 mm) in diameter and 1–3″ (2.5–7.6 cm) long. Numerous clusters may be upright, arched, or drooping. The tiny, individual flowers never actually open.

Fruits: Egg-shaped, less than 1/16″ (2 mm) long, brown to black, glossy, containing a single seed.

Habitats: Und in wet areas, such as swamps.

Some similar species.

Online References:

Www.ipm.ucdavis.edu

The Lady Bird Johnson Wildflower Center

CalPhotos at the University of California, Berkeley

Wric.ucdavis.edu (PDF)

SEINet—the Southwest Environmental Information Network

References:

Clemants, Steven; Gracie, Carol, Wildflowers in the Field and Forest, Oxford University Press, 2006, p. 76

Weakley, Alan S.; Ludwig, J. Christopher; Townsend, John F.; Crowder, Bland (Ed.), Flora of Virginia, Botanical Research Institute of Texas Press, 2013, p. 812

Persicaria incarnata (Elliott) Small
Persicaria lapathifolia (L.) Gray
Persicaria tomentosa (Schrank) E.P. Bicknell
Polygonum incarnatum Elliott
Polygonum incanum F.W. Schmidt
Polygonum lapathifolium L. var. incanum (F.W. Schmidt) W.D.J. Koch
Polygonum lapathifolium L. var. nodosum (Pers.) Small
Polygonum lapathifolium L. var. ovatum A. Braun
Polygonum lapathifolium L. ssp. pallidum (With.) Fr.
Polygonum lapathifolium L. var. prostratum Wimm.
Polygonum lapathifolium L. var. salicifolium Sibth.
Polygonum nodosum Pers.
Polygonum oneillii Brenckle
Polygonum pensylvanicum L. ssp. oneillii (Brenckle) Hultén
Polygonum scabrum Moench
Polygonum tomentosum Schrank

9/4/2020 · Wilson’s Cove Trail, Harpswell Heritage Land Trust, Harpswell, Maine · ≈ 2½ × 3½″ (7.3 × 9.4 cm)

10/5/2016 · Pine Meadow Conservation Area, Ayer, Massachusetts · ≈ 10 × 6″ (24 × 16 cm)

9/14/2023 · Nature Conservancy Access Trail, Sprague Pond, Phippsburg, Maine · ≈ 10 × 6″ (24 × 16 cm)

8/17/2013 · Hopkinton State Park, Hopkinton, Massachusetts · ≈ 9 × 6″ (23 × 16 cm) ID is uncertain

10/17/2011 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts · ≈ 12 × 8″ (31 × 20 cm) ID is uncertain

10/5/2016 · Pine Meadow Conservation Area, Ayer, Massachusetts · ≈ 7 × 5″ (18 × 13 cm)

9/17/2021 · Woodward Point Preserve, Brunswick, Maine · ≈ 3½ × 5″ (9 × 13 cm)

9/9/2017 · Habitat Loop Trail, Pine Meadow Conservation Trust Land, Groton Harvard Road, Ayer, Massachusetts · ≈ 4½ × 5″ (12 × 13 cm)

9/17/2021 · Woodward Point Preserve, Brunswick, Maine · ≈ 6 × 3½″ (14 × 9.4 cm)

8/17/2013 · Hopkinton State Park, Hopkinton, Massachusetts · ≈ 3½ × 5″ (9.1 × 12 cm) ID is uncertain

9/14/2023 · Nature Conservancy Access Trail, Sprague Pond, Phippsburg, Maine · ≈ 8 × 6″ (21 × 16 cm)

9/10/2016 · Arlington St., Groton, Massachusetts

10/17/2011 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts · ≈ 9 × 6″ (23 × 15 cm) ID is uncertain

9/4/2020 · Wilson’s Cove Trail, Harpswell Heritage Land Trust, Harpswell, Maine · ≈ 4 × 6″ (10 × 15 cm)

9/14/2023 · Nature Conservancy Access Trail, Sprague Pond, Phippsburg, Maine · ≈ 4½ × 3½″ (12 × 8.6 cm)

9/6/2023 · Beach near Cook’s Lobster and Ale House, Bailey Island, Maine

9/9/2017 · Habitat Loop Trail, Pine Meadow Conservation Trust Land, Groton Harvard Road, Ayer, Massachusetts · ≈ 7 × 4½″ (16 × 12 cm)

9/6/2023 · Beach near Cook’s Lobster and Ale House, Bailey Island, Maine

8/28/2021 · Otter Brrok Preserve, Harpswell Heritage Land Trust, Harpswell, Maine · ≈ 5 × 3½″ (13 × 9 cm)

9/4/2020 · Wilson’s Cove Trail, Harpswell Heritage Land Trust, Harpswell, Maine · ≈ 4 × 5″ (10 × 13 cm)

9/6/2023 · Beach near Cook’s Lobster and Ale House, Bailey Island, Maine

Kingdom	Plantae	Plants, but not fungi, lichens, or algae (from Stearn's Botanical Latin)
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Caryophyllidae	Cacti, many other succulents, carnivorous plants, and leadworts
Order	Caryophyllales	Includes cacti, carnations, amaranths, ice plants, and many carnivorous plants
Family	Polygonaceae	Knotweed or smartweed family
Genus	Polygonum	Greek poly, “many,” and gonu, “knee,” for the swollen jointed stems
Species	lapathifolium	“Like Lapathum,” (now the genus is called Rumex)

About plant names...

Range:

About this map...

Polygonum lapathifolium description by Thomas H. Kent, not updated.