Ludwigia palustris |
Onagraceae |
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common water-primrose, eastern false loosestrife, ludwigie palustre, marsh primrose-willow, marsh purslane, marsh seedbox, water-purslane |
evening-primrose family |
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Habit | Herbs often creeping, rooting at nodes, forming mats. | Herbs, annual or perennial, shrubs, or subshrubs, [lianas or trees], terrestrial, amphibious, or aquatic, unarmed, not clonal; often with epidermal oil cells, usually with internal phloem, abundant raphides in vegetative cells. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | prostrate or decumbent and ascending at tips, subterete or with raised lines decurrent from leaf axils, well branched, 10–50(–70) cm, glabrous or, sometimes, minutely strigillose on leaf margins and inflorescence. |
erect to decumbent or prostrate. |
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Leaves | opposite; stipules narrowly deltate, 0.05–0.1 × 0.05–0.1 mm; petiole narrowly winged, 0.1–2.5 cm, blade narrowly to broadly elliptic or ovate-elliptic, 0.5–4.5 × 0.3–2.3 cm, base abruptly attenuate, margins entire and minutely strigillose, apex subacute, surfaces glabrous; bracts not reduced. |
usually deciduous, usually alternate or opposite, sometimes whorled, simple, usually cauline, sometimes basal and forming rosettes; stipules present, intrapetiolar, usually caducous, relatively small, or absent (tribes Epilobieae and Onagreae); sessile or subsessile to petiolate; blade margins usually entire, toothed, or pinnately lobed, rarely bipinnately lobed. |
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Inflorescences | leafy spikes or racemes, flowers usually paired in leaf axils of prostrate stems; bracteoles attached at base or to 2.5 mm distal to base of ovary, sublinear, 0.3–1(–1.8) × 0.1–0.8 mm. |
axillary, flowers solitary, leafy spikes, racemes, or panicles. |
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Flowers | sepals ascending, green, ovate-deltate, 1.1–2 × 1–2.1 mm, margins finely serrulate with minute hairs, apex acuminate, sometimes with blunt tip, surfaces glabrous; petals 0; filaments translucent, 0.4–0.6 mm, anthers 0.2–0.4 × 0.3–0.6 mm; pollen shed singly; ovary oblong, 1.5–3.5 × 1–2 mm, glabrate; nectary disc elevated 0.15–0.3 mm on ovary apex, green, 1–2 mm diam., 4-lobed, glabrous; style pale green, 0.3–0.7 mm, glabrous, stigma subglobose or capitate, 0.4–0.6 × 0.2–0.4 mm, not exserted beyond anthers. |
usually bisexual, (protandrous in Chamaenerion, Clarkia, Epilobium, [and most species of Lopezia]; protogynous in Circaea and Fuchsia), sometimes unisexual (gynodioecious or dioecious, [subdioecious]), usually actinomorphic, sometimes zygomorphic, (2–)4(–7)-merous; perianth and androecium epigynous; sepals persistent after anthesis (in Ludwigia), or all flower parts deciduous after anthesis; floral tube present or absent in Chamaenerion, Ludwigia, [and most species of Lopezia]; sepals usually green or red, rarely pink or purple, valvate; petals present, rarely absent, often fading darker with age, imbricate or convolute, sometimes clawed; nectary present; stamens 2 times as many as sepals and in 2 series, antisepalous set usually longer, rarely all equal (Chamaenerion), or as many as sepals, [in Lopezia reduced to 2 or 1 plus 1 sterile staminode]; filaments distinct; anthers usually versatile, sometimes basifixed, dithecal, polysporangiate, with tapetal septa, sometimes also with parenchymatous septa, opening by longitudinal slits, pollen grains united by viscin threads, (2 or)3(–5)-aperturate, shed singly or in tetrads or polyads; ovary inferior, usually with as many carpels and locules as sepals, rarely 1 or 2 (Circaea and Gayophytum), septa sometimes thin or absent at maturity; placentation axile or parietal; style 1, stigma 1, with as many lobes as sepals or clavate to globose, papillate or not, and wet with free-running secretions to dry without the secretions; ovules 1 to numerous per locule, in 1 or several rows or clustered, anatropous, bitegmic. |
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Fruit | a loculicidal capsule or indehiscent berry or nutlike. |
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Capsules | oblong obovoid, 4-angled, (1.6–)2–5 × 1.5–3(–3.5) mm, thin-walled, irregularly dehiscent or dispersing as unit, pedicel 0–0.5 mm. |
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Seeds | yellowish brown, ellipsoid, 0.5–0.7 × 0.3–0.4 mm, surface cells transversely elongate. |
smooth or sculptured, sometimes with a coma or wings, with straight, oily embryo, 4-nucleate embryo sac, endosperm absent. |
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2n | = 16. |
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Ludwigia palustris |
Onagraceae |
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Phenology | Flowering Feb–Oct. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Roadside ditches, wet meadows, dried pond bottoms, margins of ponds, swamps, rivers, alluvial sand bars. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 0–1000[–2700] m. (0–3300[–8900] ft.) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; BC; NB; NF; NS; ON; QC; Mexico (Chiapas, Chihuahua, Guerrero, Hidalgo, Jalisco, México, Michoacán, Morelos, Nuevo León, Oaxaca, San Luis Potosí, Sinaloa, Sonora, Tamaulipas, Veracruz); West Indies (Cuba, Hispaniola, Jamaica, Puerto Rico); Bermuda; Central America (Costa Rica, Guatemala, Panama); South America (Colombia, Peru, Venezuela); Europe; sw Asia; Africa; introduced in Pacific Islands (Hawaii, New Zealand); Australia
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North America; Mexico; Central America; South America; West Indies; Bermuda; Eurasia; Africa; Atlantic Islands; Indian Ocean Islands; Pacific Islands; Australasia; nearly worldwide; primarily New World |
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Discussion | Ludwigia palustris is a common diploid and most widely distributed species in sect. Isnardia. It is particularly widespread in temperate North America and in Europe [the type is thought to be from Europe (P. H. Raven 1963[1964]; C. I. Peng et al. 2005)], more sporadically in Africa and sw Asia, and introduced in Australasia, and Hawaii. The close sister relationship of sect. Isnardia with sect. Miquelia (L. ovalis Miquel only, endemic to eastern Asia) suggests that this clade may have had a history connected with the evolution of the Arcto-Tertiary Geoflora (P. H. Raven and D. I. Axelrod 1974; Peng et al.). Ludwigia palustris is known to hybridize with L. brevipes producing the sterile L. ×lacustris Eames. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 22, species 664 (17 genera, 277 species in the flora). Members of the Onagraceae are especially richly represented in North America. The family comprises annual and perennial herbs, with some shrubs and a few small to medium-sized trees. Most species occur in open habitats, ranging from dry to wet, with a few species of Ludwigia aquatic, from the tropics to the deserts of western North America, temperate forests, and arctic tundra; some species of Epilobium, Ludwigia, and Oenothera can be weeds in disturbed habitats. Members of the family are characterized by 4-merous flowers (sometimes 2-, 5-, or 7-merous), an inferior ovary, a floral tube in most species, stamens usually two times as many as sepals, and pollen connected by viscin threads. Flowers are usually bisexual, sometimes unisexual, and plants are gynodioecious, matinal, diurnal, or vespertine, self-compatible or self-incompatible, often outcrossing and then pollinated by a wide variety of insects or birds, or autogamous (P. H. Raven 1979; W. L. Wagner et al. 2007). Onagraceae are known in considerable systematic detail, and information is available on comparative breeding systems and pollination biology, on chromosome numbers and cytogenetic relations, often involving translocations, and on vegetative, floral, and seed anatomy, palynology, and embryology. The phylogeny of the family is known in reasonably good detail, with most parts of the trees generally well-supported. The suprageneric and generic classification presented by W. L. Wagner et al. (2007) differs in a number of ways from the previous classification (P. H. Raven 1979, 1988). Onagraceae are divided into two subfamilies based on a fundamental basal split recognized in all phylogenetic studies (R. H. Eyde 1981; P. C. Hoch et al. 1993; R. A. Levin et al. 2003, 2004; V. S. Ford and L. D. Gottlieb 2007), with Ludwigia on one branch (as Ludwigioideae), and the rest of the family on a second branch (as Onagroideae). Onagroideae are subdivided into six tribes: Circaeeae (including Fuchsieae), Epilobieae, Gongylocarpeae, Hauyeae, Lopezieae, and Onagreae. The Epilobieae and Onagreae are diverse; together they constitute fully two-thirds of the species in the family and include 15 of the 22 genera. The classification following Wagner et al. can be viewed on the Onagraceae web site by Wagner and Hoch at http://botany.si.edu/Onagraceae. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 10. | FNA vol. 10. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Isnardia | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | Isnardia palustris, I. ascendens, I. nitida, I. palustris var. americana, L. apetala, L. nitida, L. palustris var. americana, L. palustris var. inundata, L. palustris var. liebmannii, L. palustris var. nana, L. palustris var. pacifica | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | (Linnaeus) Elliott: Sketch Bot. S. Carolina 1: 211. (1817) | Jussieu | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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