Ludwigia hexapetala |
Ludwigia hirtella |
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false loosestrife, large-flower primrose-willow, primrose willow, six petal water primrose, Uruguayan primrose-willow, water primrose |
hairy seedbox, Rafinesque's seedbox, spindleroot |
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Habit | Herbs, subshrubs, or emergent aquatics, adventitious roots sometimes forming a thick mass 10–23 cm at submerged nodes, sometimes woody at base, white pneumatophores 5–10 cm often on submerged stems. | |
Roots | fusiform, somewhat thickened, often fascicled. |
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Stems | floating or creeping and ascending to erect, terete, 20–200(–400) cm, simple to densely branched apically, glabrous (floating) or sparsely to densely villous (emergent), sometimes villous only on inflorescence. |
subterete to angled, with raised lines or narrow wings decurrent from leaf axils, (30–)50–120 cm, well branched in distal 1/2, densely erect-hirsute to sometimes glabrous. |
Leaves | stipules ovate or deltate, 0.7–2 × 0.5–1.1 mm, not succulent, apex subacute, mucronate; petiole flattened, 0.5–2(–2.5) cm; blade narrowly oblanceolate, narrowly elliptic, or lanceolate to obovate or spatulate, (1.5–)4.2–10.7(–13.5) × (0.5–)0.8–3 cm, chartaceous, base cuneate or attenuate, margins entire, apex acute to obtuse, rounded or truncate, sometimes mucronate, surfaces not shiny, usually glabrous, sometimes villous on petiole and veins or throughout; bracts not reduced. |
stipules narrowly deltate, 0.05–0.15 × 0.05–0.1 mm; sessile; blade closely appressed to stem, lanceolate to ovate-oblong, 1.4–5.5 × 0.4–1.2 cm, base attenuate, margins entire, apex acute to rounded, surfaces glabrous or densely erect-hirsute; bracts usually very reduced, sublinear. |
Inflorescences | emergent stems sometimes in leafy racemes, sometimes reflexed, flowers solitary in leaf axils; bracteoles obovate to narrowly obovate, 1–1.8 × 0.7–0.8 mm, apex acute or acuminate, attached on distal 1/2 of pedicel or at ovary base. |
leafy racemes, flowers solitary in leaf axils; bracteoles attached in subopposite pairs just proximal to ovary base, lanceolate-linear, 2.5–7 × 0.5–1.5 mm, margins entire, apex acute, surfaces hirtellous. |
Flowers | sepals ovate-deltate or lanceolate-deltate, (8–)12–19 × 2–5 mm, chartaceous, margins entire, apex acuminate, surfaces ± densely villous; petals bright yellow, sometimes with orange base, fan-shaped, (15–)20–30 × (12–)16–25 mm, apex emarginate or mucronate; stamens 10(or 12), in 2 unequal series, yellow, filaments recurved, shorter ones (1.6–)2.3–5.2 mm, longer ones (3.1–)3.6–7.5 mm, anthers oblong, (1.2–)1.7–4 × 1–1.5 mm; ovary subcylindric, terete, 10–18 × 2–3 mm, apex ± broadened, glabrous or sparsely to densely villous; nectary disc slightly raised on ovary apex, yellowish green, 2–4 mm diam., lobed, glabrous or ringed with white hairs; style yellow, 6–10 mm, glabrous, stigma subcapitate-globose, 0.5–1.5 × 1.5–2.5 mm, often exserted beyond anthers. |
sepals narrowly ovate-deltate, (5.4–)6–12 × 2.2–4.5(–5) mm, margins entire, apex acute, surfaces hirtellous or, sometimes, glabrous; petals cordate, 12–14 × 13–14 mm, base attenuate, apex emarginate; filaments opaque white, awl-shaped, 2–5.5 mm, anthers 1.4–2.6 × 0.4–0.8 mm; ovary subcuboid or globose, 3–4 × 3–4 mm; nectary disc elevated, domed, 1–1.4 mm diam., prominently 4-lobed, ringed with stiff, spreading hairs or glabrous; style 1.3–4.5(–5.5) mm, glabrous, stigma capitate to hemispherical, 0.9–1.5 × 0.9–2(–2.5) mm, often shallowly 4-lobed, as long as stamens, sometimes exserted beyond them. |
Capsules | cylindric or subclavate, terete, sometimes curved, (12–)16–24(–30)× 2.5–4 mm, with thick woody walls, irregularly and tardily dehiscent, pedicel (9–)13–25(–85) mm. |
subcuboid to squarish globose, 4–6 × 4–5 mm, 4-angled, often also 4-winged, wings 0.3–1.1 mm wide, pedicel 3–10 mm. |
Seeds | embedded in wedge-shaped piece of endocarp, 0.8–1 × 0.8–1 mm. |
light brown, oblong to reniform, 0.6–0.7 × 0.3–0.4 mm, surface cells elongate transversely to seed length. |
2n | = 80. |
= 16. |
Ludwigia hexapetala |
Ludwigia hirtella |
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Phenology | Flowering spring–late fall. | Flowering summer–early fall. |
Habitat | Wet places, along slow-moving rivers, streams, canals, ditches, often growing into main channel as aquatic weed. | Boggy depressions, roadside ditches, margins of boggy streams. |
Elevation | 0–200[–2600] m. (0–700[–8500] ft.) | 0–300 m. (0–1000 ft.) |
Distribution |
AL; AR; CA; FL; GA; KY; LA; MS; NC; NY; OR; PA; SC; TN; WA; Central America (Costa Rica); South America (Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay) [Introduced in w Europe (Belgium, France, Spain)]
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AL; AR; DC; DE; FL; GA; KY; LA; MD; MS; NC; NJ; OK; SC; TN; TX; VA
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Discussion | Ludwigia hexapetala (2n = 80) was formerly included with L. grandiflora (2n = 48) in L. uruguayensis (Cambessèdes) H. Hara, and some authors (G. L. Nesom and J. T. Kartesz 2000) still consider them to be a single species. The small but consistent morphological differences and different ploidy levels argue for keeping them distinct at the species level. Fernald described Jussiaea michauxiana (1944), since he thought that J. grandiflora Michaux (1803) was a homonym (not J. grandiflora Ruíz & Pavon). However, it was later determined that the volume containing the Ruíz & Pavon name was published in 1830 (not 1802) making the name by Michaux valid and legitimate, and the name by Fernald an illegitimate substitution. Plants now known as Ludwigia hexapetala were included in the circumscription of L. uruguayensis (Cambessèdes) H. Hara (based on J. uruguayensis Cambessèdes) by P. H. Raven (1963[1964]) and P. A. Munz (1965). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
A name often found in synonymy with Ludwigia hirtella is a later homonym: L. hirsuta Pursh 1813, not Desrousseaux 1789. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Jussiaea | Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Ludwigia |
Sibling taxa | ||
Synonyms | Jussiaeahexapetala hooker, J. repens var. major, L. grandiflora subsp. hexapetala, L. grandiflora var. hexapetala, L. uruguayensis var. major | Isnardia hirsuta var. permollis, I. hirtella, L. permollis |
Name authority | (Hooker & Arnott) Zardini, H. Y. Gu & P. H. Raven: Syst. Bot. 16: 243. (1991) | Rafinesque: Med. Repos., hexade 2, 5: 358. (1808) |
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