Ludwigia spathulata |
Ludwigia maritima |
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southern water purslane, spoon primrose-willow |
seaside primrose-willow |
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Habit | Herbs creeping and rooting at nodes, often forming mats. | |
Roots | fibrous or fusiform, sometimes fascicled. |
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Stems | prostrate or decumbent and ascending distally, slightly ridged, well branched, 10–40cm, densely strigillose throughout. |
subterete to scarcely angled, with narrow raised lines or wings decurrent from leaf axils, 30–90 cm, simple or sparsely branched distally, strigillose to sometimes glabrate. |
Leaves | opposite; stipules narrowly deltate or ovate, 0.05–0.15 × 0.05–0.1 mm; petiole very narrowly winged, 0.3–0.9 cm, blade elliptic-spatulate or narrowly so, 0.9–1.7 × 0.3–0.9 cm, base attenuate, margins entire, apex acute, surfaces strigillose; bracts not reduced except at branch tips. |
stipules narrowly deltate, 0.05–0.2 × 0.05–0.1 mm; sessile; blade ovate proximally, lanceolate to lanceolate-linear distally, (2–)3–8 × 0.3–1.5 cm, base cuneate, margins entire, apex acute, surfaces glabrate to strigillose or hirsute; bracts usually much reduced, sublinear. |
Inflorescences | leafy spikes or racemes, flowers usually paired in leaf axils; bracteoles attached at base of ovary or on short pedicel, narrowly oblong or oblanceolate, 0.2–0.8 × 0.05–0.2 mm, apex acute, often obscured by hairs. |
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, pale green, broadly ovate-deltate, 1–1.7 × 1.1–1.7 mm, margins entire, apex acuminate, surfaces densely strigillose; petals 0; filaments translucent, 0.5–0.8 mm, anthers 0.2–0.4 × 0.3–0.5 mm; pollen shed singly; ovary oblong-obovoid, 4-angled to subterete, 1.5–2.5 × 1–1.5 mm; nectary disc elevated 0.1–0.2 mm on ovary apex, yellowish green, 0.7–0.9 mm diam., 4-lobed, glabrous; style yellowish green, 0.3–0.5 mm, glabrous, stigma pale yellow, capitate, 0.2–0.3 × 0.2–0.3 mm, not exserted beyond anthers. |
sepals often spreading, ovate-deltate, (4.5–)5.5–8(–9) × 3–5 mm, margins entire, apex acute to obtuse, surfaces strigillose; petals cordate, 9–12 × 8–10 mm, base attenuate, apex emarginate; filaments yellow, awl-shaped, 1.9–3.2 mm, anthers 1.2–2.5 × 0.4–0.7 mm; ovary subcuboid or globose, 3–4.5 × 3–4 mm; nectary disc elevated, domed, 0.9–1.3 mm diam., prominently 4-lobed, ringed with sparse, spreading hairs; style 1.5–3.3 mm, glabrous, stigma capitate to hemispherical, 0.6–1.2 × 1.4–1.9 mm, shallowly 4-lobed, not exserted beyond anthers. |
Capsules | oblong-obovoid, subterete, 2.5–4(–4.5) × 1.5–2.5 mm, thin-walled, seeds often visible on exocarp as small bumps, irregularly dehiscent or dispersing as unit, pedicel 0–0.5 mm. |
subcuboid to squarish globose, 4–7 ×4–5 mm, 4-angled, often also 4-winged, wings 0.3–1.2 mm wide, pedicel 5–17 mm. |
Seeds | dark reddish brown, ellipsoid, 0.5–0.7 × 0.4–0.5 mm, surface cells transversely elongate. |
light brown, oblong to reniform, 0.4–0.6 ×0.2–0.4 mm, surface cells elongate transversely to seed length, except may be parallel to seed length near raphe. |
2n | = 32. |
= 16. |
Ludwigia spathulata |
Ludwigia maritima |
|
Phenology | Flowering summer. | |
Habitat | Damp, sandy, or peaty habitats, roadside ditches, margins of bogs or fields, usually within 75 miles of sea coast. | |
Elevation | 0–200 m. (0–700 ft.) | |
Distribution |
AL; FL; GA; LA; MS; NC; SC
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Discussion | Flowers May–Sep. Ditches, swales, edges of ponds, lakes, sinks, swamps, sandy river bars, dried seasonal ponds, disturbed low savannas; of conservation concern; 0–200 m; Ala., Fla., Ga., S.C. The tetraploid Ludwigia spathulata is relatively uncommon and occurs primarily on the Gulf Coastal Plain in the panhandle of Florida, southern Alabama, and southwestern Georgia. Outlying populations have also been collected in transitional areas between the Coastal Plain and the Piedmont in South Carolina and Georgia. With its small apetalous flowers, L. spathulata is modally autogamous and shows low morphological variability. Its strongest affinities appear to be with L. palustris, with which it shares a genome (C. I. Peng 1988, 1989). (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 spathulata | |
Name authority | Torrey & A. Gray: Fl. N. Amer. 1: 526. (1840) | R. M. Harper: Torreya 4: 163, fig. 2. (1904) |
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