Ludwigia spathulata |
Ludwigia erecta |
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southern water purslane, spoon primrose-willow |
yerba de jicotea |
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Habit | Herbs creeping and rooting at nodes, often forming mats. | Herbs annual, rarely persistent a second year from woody base. |
Stems | prostrate or decumbent and ascending distally, slightly ridged, well branched, 10–40cm, densely strigillose throughout. |
erect, 4-angled, rarely 4-winged, sometimes basally terete, 40–280 cm, simple to densely branched, branches often ascending, glabrous. |
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 deltate, 0.2–0.3 × 0.15–0.2 mm; petiole 0.2–2.2 cm, somewhat flattened and continuous with ridges or wings on stem; blade elliptic to narrowly lanceolate, 2–20 × 0.2–4 cm, base cuneate, margins minutely scabrid, apex acute or acuminate, membranous, surfaces glabrous or sometimes minutely strigillose along abaxial veins; bracts often reduced. |
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. |
leafy spikes, flowers solitary in distal axils; bracteoles attached at base of ovary or on lower 1/2, without subtending glands, deltate, 0.3–0.5 × 0.2–0.3 mm, apex acute. |
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 ovate or lanceolate, 3–6 × 1–2 mm, apex acute or short-acuminate, surfaces usually glabrous, sometimes strigillose; petals obovate, 3.5–5 × 2–2.5 mm; stamens 8 in 2 subequal series, filaments 1.3–1.5 mm, anthers oblong, 0.6–1 × 0.4–0.5 mm; ovary obconic, 4-angled, 4–10 × 2–4 mm, usually glabrous, rarely strigillose; nectary disc plane on ovary apex, 3–4 mm diam., 4-lobed, glabrate; style 0.5–1.5 × 0.5–0.6 mm, stigma globose, 0.8–1 × 1–1.2 mm, not exserted beyond anthers and pollen shed directly on it. |
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. |
oblong-linear to squarish-cylindric, 4-angled, 10–22 × 2–4 mm, thin-walled, irregularly dehiscent, subsessile. |
Seeds | dark reddish brown, ellipsoid, 0.5–0.7 × 0.4–0.5 mm, surface cells transversely elongate. |
elongate-ovoid, 0.3–0.5 × 0.2–0.3 mm, raphevery reduced and inconspicuous. |
2n | = 32. |
= 16. |
Ludwigia spathulata |
Ludwigia erecta |
|
Phenology | Flowering summer–early fall. | |
Habitat | Pond margins and depressions, wet sand ditches and prairies. | |
Elevation | 0–100[–300] m. (0–300[–1000] ft.) | |
Distribution |
AL; AZ; FL; Central America; South America; Mexico (Campeche, Chiapas, Jalisco, Michoacán, Nayarit, Oaxaca, Tabasco); West Indies; Africa (Nigeria, Tanzania); Indian Ocean Islands (Comoros Islands, Madagascar, Seychelles) |
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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.) |
Ludwigia erecta, which is morphologically similar to L. decurrens and often growing with it, is modally self-pollinating and is usually easy to distinguish from that species. Although Ludwigia erecta is widely distributed in warm temperate regions in the New World and Africa, it appears to be most closely related to species restricted to South America. Its appearance in a rather remote locality in Arizona in 2006 may be attributable to transport there in mud on migrating birds. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Isnardia spathulata | Jussiaea erecta, Isnardia discolor, J. acuminata, J. acuminata var. latifolia, J. acuminata var. longifolia, J. altissima, J. declinata, J. erecta var. plumeriana, J. erecta var. sebana, J. onagra, J. plumeriana, J. ramosa, L. acuminata |
Name authority | Torrey & A. Gray: Fl. N. Amer. 1: 526. (1840) | (Linnaeus) H. Hara: J. Jap. Bot. 28: 292. (1953) |
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