Ludwigia octovalvis |
Ludwigia virgata |
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Mexican primrose-willow |
savannah primrose-willow |
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Habit | Herbs (robust)or shrubs, herbs tap-rooted, often woody at base, with peeling bark. | |
Roots | fascicled, often fusiform, or spreading horizontally. |
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Stems | erect to spreading, terete or sometimes ridged, 60–250(–400) cm, densely branched, densely villous to glabrate, especially near base. |
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 | stipules deltate, 0.5–0.8 × 0.6–0.7 mm, fleshy; petiole 0–1 cm; blade linear to oblong or oblanceolate, sometimes narrowly ovate, 0.7–14.5 × 0.1–4 cm, base tapered, margins entire, apex acute to acuminate, surfaces ± densely villous or strigillose; bracts not or scarcely 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 | open, leafy racemes, flowers solitary in axils, presentation often radial; bracteoles ovate, 3–8 × 1.4–4 mm, apex acuminate, attached near base of ovary. |
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 lanceolate to ovate, (6–)8–13 × 3–7 mm, apex acuminate, surfaces strigillose adaxially; petals bright yellow, fan-shaped, (5–)10–20 × 5–20 mm, apex sometimes shallowly notched; stamens 8 in 2 subequal series, yellowish white, filaments spreading, 4–6 mm, anthers oblong, 2.5–5 × 1–2 mm; pollen shed in tetrads or sometimes polyads; ovary cylindric, 4-angled, sometimes slightly twisted, 8–22 × 1–3 mm; nectary disc elevated 0.4–0.5 mm on ovary apex, 1–2.4 mm diam., with 4 white-pubescent sunken lobes opposite petals; style 2.5–3.5 mm, stigma capitate-globose, 1.8–3.5 × 2.5–3.5 mm, surrounded by anthers and pollen shed directly on it. |
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 | cylindric to clavate-cylindric, subterete to ± 4-angled, 17–50 × 2.5–8 mm, thin-walled, irregularly dehiscent by 4–8 linear valves splitting from apex, short-villous, pedicel 5–25 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 | in several indistinct rows per locule, broad-cylindric with rounded ends, 0.6–0.9 × 0.5–0.8 mm, raphe inflated and nearly equal to seed body. |
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], 32, 48. |
= 16. |
Ludwigia octovalvis |
Ludwigia virgata |
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Phenology | Flowering summer–early fall. | Flowering summer. |
Habitat | Wet or moist places, along coasts, streams, ditches, swamps, often near disturbance or cultivation. | Sandy savannas, pinelands, damp roadside ditches, margins of ponds, bogs, irrigated fields, usually within 75 miles of sea coast. |
Elevation | 0–300[–2200] m. [0–1000[–7200] ft.] | 0–300 m. [0–1000 ft.] |
Distribution |
AL; FL; GA; LA; MS; NC; SC; TX; Mexico; Central America; South America; West Indies; s Asia; e Asia (Burma, China, India, Japan, Thailand, Vietnam); Africa; Indian Ocean Islands (Comoros Islands, Madagascar); Pacific Islands (New Caledonia, Papua New Guinea, Philippines)
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AL; FL; GA; MS; NC; SC; VA
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Discussion | Ludwigia octovalvis is perhaps the most widespread species of Ludwigia worldwide and exhibits a very complex pattern of morphological and ecological variation, correlated only in part with multiple ploidy levels; this complexity is reflected in its extensive synonymy. P. H. Raven (1963[1964]), P. A. Munz (1942, 1965), and others have proposed formal classifications to account for this variation, with mixed results and additional study using more powerful analytical tools is clearly needed in order to develop a more stable classification. In the absence of better understanding, and despite some correlated patterns of morphological and geographical variation on a global scale, this treatment does not recognize infraspecific taxa. Jussiaea hirsuta Velloso, J. suffruticosa var. angustifolia Chodat & Hassler, J. velutina Kunze, and Ludwigia suffruticosa (Linnaeus) M. Gómez are later homonyms; these four names pertain here. (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 | Oenothera octovalvis, Jussiaea calycina, J. clavata, J. frutescens, J. haenkeana, J. hirta, J. ligustrifolia, J. occidentalis, J. octofila, J. octonervia, J. octonervia var. sessiliflora, J. octovalvis, J. parviflora, J. peruviana var. octofila, J. pubescens, J. sagrana, J. salicifolia, J. scabra, J. suffruticosa, J. suffruticosa var. ligustrifolia, J. suffruticosa var. linearifolia, J. suffruticosa var. octofila, J. suffruticosa subsp. octonervia, J. suffruticosa var. octonervia, J. suffruticosa var. sessiliflora, J. suffruticosa var. sintenisii, J. venosa, J. villosa, L. octovalvis var. ligustrifolia, L. octovalvis var. octofila, L. octovalvis subsp. sessiliflora, L. octovalvis var. sessiliflora, L. pubescens, L. pubescens var. ligustrifolia, L. pubescens var. linearifolia, L. pubescens var. sessiliflora, L. sagrana | Isnardia virgata |
Name authority | (Jacquin) P. H. Raven: Kew Bull. 15: 476. (1962) | Michaux: Fl. Bor.-Amer. 1: 89. (1803) |
Web links |