Polygonella americana

(Fischer & C. A. Meyer) Small

Mem. Torrey Bot. Club 5: 141. 1894.

Common names: American jointweed southern jointweed
Basionym: Gonopyrum americanum Fischer & C. A. Meyer Mém. Acad. Imp. Sci. Saint-Pétersbourg, Sér. 6, Sci. Math., Seconde Pt. Sci. Nat. 4: 144. 1840
Treatment appears in FNA Volume 5. Treatment on page 539. Mentioned on page 535.

Subshrubs, perennial, synoecious, 5.5–9 dm. Stems erect, branched proximally and basally, glabrous. Leaves persistent; ocrea margins not ciliate; blade linear to spatulate, (4–)5–12(–19) × 0.5–0.9(–1.2) mm, base barely tapered, margins not hyaline, apex obtuse to acute, often erose, glabrous. Inflorescences (7–)18–30(–60) mm; ocreola encircling rachis, only the base adnate to rachis, apex acuminate. Pedicels spreading in anthesis and fruit, 0.4–2.3 mm, usually much longer than subtending ocreola. Flowers bisexual; outer tepals sharply reflexed early in anthesis and in fruit, white to pink, elliptic to ovate, 1.2–2.2 mm in anthesis, margins erose; inner tepals loosely appressed in anthesis and fruit, white to pink, ovate to suborbiculate, 1.7–2.9 mm in anthesis, margins erose; filaments dimorphic; anthers yellow or pink; styles and stigmas 0.5–1 mm in anthesis. Achenes included, reddish brown, 3(–4)-gonous, 2.5–4 × 1.3–2.3 mm, shiny, smooth. 2n = 36.

Phenology: Flowering Jun–Oct.
Habitat: Sandy roadsides, fields, riverbanks, scrub forests, waste places
Elevation: 10-200 m


V5 1105-distribution-map.gif

Ala., Ark., Ga., La., Mo., N.Mex., Okla., S.C., Tex.


Selected References


Lower Taxa

... more about "Polygonella americana"
Craig C. Freeman +
(Fischer & C. A. Meyer) Small +
Gonopyrum americanum +
American jointweed +  and southern jointweed +
Ala. +, Ark. +, Ga. +, La. +, Mo. +, N.Mex. +, Okla. +, S.C. +  and Tex. +
10-200 m +
Sandy roadsides, fields, riverbanks, scrub forests, waste places +
Flowering Jun–Oct. +
Mem. Torrey Bot. Club +
Illustrated +  and Endemic +
Polygonella americana +
Polygonella +
species +