Ludwigia linifolia |
Ludwigia virgata |
|
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flaxleaf seedbox, southeastern primrose-willow |
savannah primrose-willow |
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Habit | Herbs slender, rarely with aerenchyma, forming slender stolons 4–15(–30) cm, 0.7–1(–1.5) mm thick. | |
Roots | fascicled, often fusiform, or spreading horizontally. |
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Stems | erect or ascending, slightly ridged, usually well branched, 12–55(–62) cm, glabrous. |
subterete to scarcely angled, with narrow raised lines or wings decurrent from leaf axils, 45–85 cm, branched mainly near base, glabrate with strigillose raised lines or strigillose. |
Leaves | alternate; stipules narrowly ovate to narrowly lanceolate, 0.2–0.3 × 0.1–0.2 mm; stolons: petiole narrowly attenuate, 0.05–0.5 cm, blade narrowly obovate or oblanceolate to spatulate, 0.5–2 × 0.1–0.6 cm; stems: sessile, blade linear to linear-oblanceolate, 1.5–4 × 0.1–0.4(–0.6) cm, base very narrowly cuneate, margins entire with obscure hydathodal glands, apex acuminate to acute; bracts linear, reduced. |
stipules narrowly deltate, 0.1–0.2 × 0.1–0.15 mm; sessile; blade ovate to obovate proximally, lanceolate-linear to linear distally, 2–7 × 0.2–1(–1.5) cm, base cuneate, margins entire, apex acute to rounded, surfaces strigillose, densely so particularly along veins; bracts usually very reduced in size, sublinear. |
Inflorescences | leafy spikes, flowers solitary in leaf axils; bracteoles attached 0–1.5 mm distal to base of ovary, very narrowly oblanceolate to linear, (1.5–)2.5–9(–13) × 0.2–0.8 mm, margins entire, apex acute. |
sparse racemes, flowers solitary in leaf axils; bracteoles attached in subopposite pairs on distal 1/3 of pedicel, lanceolate-linear, 0.7–3.2(–5) ×0.2–0.5 mm, margins entire, apex acute, surfaces strigillose. |
Flowers | sepals ascending, green, narrowly lanceolate-deltate, (3–)4–7 × 1.1–1.7 mm, margins entire, apex narrowly acute, surfaces glabrous or minutely papillose; petals narrowly obovate-elliptic, 4–6 × 2–4 mm, base obtuse, apex obtuse or rounded; filaments pale yellow, (1.3–)1.5–2.5(–3) mm, anthers oblong, 0.6–1.1 × 0.5–0.8 mm; pollen shed in tetrads; ovary subcylindric, 3–4 × 1–1.5 mm; nectary disc elevated 0.3–0.7 mm on ovary apex, bright yellow, 0.8–1.5 mm diam., prominently 4-lobed, minutely papillose; style yellow, 1.25–2.5 mm, glabrous, stigma subcapitate, 0.3–0.6 × 0.6–0.8 mm, shallowly 4-lobed, not exserted beyond anthers. |
sepals strongly reflexed, narrowly ovate-deltate, 6–10 × 2.5–4.5 mm, margins entire, apex acute, surfaces finely strigillose to glabrate; petals cordate, 14–19 × 13–15 mm, base attenuate, apex emarginate; filaments opaque white, awl-shaped, 1.9–4.2 mm, anthers 2–4 × 0.6–1 mm; ovary subcuboid to globose, 3–4 × 3–4 mm; nectary disc elevated, domed, 0.8–1.4 mm diam., prominently 4-lobed, ringed with silky-curly hairs; style 5–9.5 mm, glabrous, stigma capitate to hemispherical, 0.6–1.3 × 1.3–2.6 mm, shallowly 4-lobed, as long as or exserted beyond anthers. |
Capsules | subcylindric, terete or slightly angled, 5–10(–12) ×1.3–2(–2.2) mm, hard-walled, irregularly dehiscent, pedicel 0 mm. |
subglobose to ellipsoid, 3.5–6.8 × 3.3–4.3 mm, 4-angled, angles not developed into wings, pedicel 6.5–17 mm. |
Seeds | reddish brown, oblong-elliptic, 0.6–0.7 × 0.2–0.3 mm, surface cells nearly isodiametric. |
light brown, elliptic-oblong to reniform, 0.5–0.7 × 0.3–0.4 mm, surface cells elongate transversely to seed length or elongate parallel to length near raphe. |
2n | = 16. |
= 16. |
Ludwigia linifolia |
Ludwigia virgata |
|
Phenology | Flowering late Jun–Oct. | Flowering summer. |
Habitat | Drainage ditches, margins of creeks or swamps, open edges of cypress swamps, moist pinelands, edges of brackish lakes. | Sandy savannas, pinelands, damp roadside ditches, margins of ponds, bogs, irrigated fields, usually within 75 miles of sea coast. |
Elevation | 0–300 m. (0–1000 ft.) | 0–300 m. (0–1000 ft.) |
Distribution |
AL; FL; GA; MS; NC; SC; Mexico (Tabasco) |
AL; FL; GA; MS; NC; SC; VA
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Discussion | Ludwigia linifolia is primarily a coastal species that extends farther inland in Georgia and the Carolinas. Being one of five diploids in sect. Isnardia, it has particularly prominent nectary lobes and appears to be modally outcrossing (C. I. Peng 1989). It also is known from a disjunct population on the Yucatán Peninsula in Tabasco, Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Isnardia linifolia | Isnardia virgata |
Name authority | Poiret in J. Lamarck et al.: Encycl., Suppl. 3: 513. (1814) | Michaux: Fl. Bor.-Amer. 1: 89. (1803) |
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