Ludwigia bonariensis |
Ludwigia pilosa |
|
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Carolina primrose-willow |
hairy primrose-willow |
|
Habit | Herbs, from woody rootstock. | Herbs often with prominent aerenchyma when base submerged, forming stolons 30–250 cm, 2–4 mm thick, creeping in mud or floating in water, sometimes bearing flowers and fruits. |
Stems | erect, subterete, 20–120 cm, branched, glabrate proximally, or strigillose, especially in distal parts, with raised strigillose lines decurrent from leaf axils mid stem. |
erect, subterete, densely branched, 40–120 cm, densely hirtellous. |
Leaves | stipules narrowly deltate, 0.3–0.5 × 0.1–0.2 mm; petiole winged, 0.1–0.7 cm; blade narrowly to broadly lanceolate, 4–15 × 0.3–1(–3) cm, base tapered, margins subentire to inconspicuously glandular-serrulate, apex acute to acuminate, surfaces finely strigillose, especially on abaxial veins, sometimes glabrate; bracts narrower, reduced in size. |
alternate; stipules ovate to lanceolate, 0.2–0.25 × 0.1–0.15 mm, usually obscured by pubescence; stolons: petiole 0.2–0.7 cm, blade obovate or elliptic to orbiculate, 0.6–2 × 0.5–1.1 cm, margins with distinct hydathodal teeth, base attenuate, surfaces densely hirtellous to glabrate; stems: petiole 0–0.2(–1) cm, blade elliptic or lanceolate-elliptic to very narrowly elliptic, 1.5–8(–10) × 0.3–1.2(–1.4) cm, base cuneate or attenuate, margins entire with obscure hydathodal glands, apex acute or narrowly acute, surfaces ± densely hirtellous, leaves on branches much reduced; bracts much reduced. |
Inflorescences | open, leafy racemes, flowers solitary in axils; bracteoles lanceolate-linear or setaceous, 2–6 × 0.3–0.8 mm, attached on pedicel just proximal to base of ovary. |
usually congested, leafy spikes or racemes, flowers solitary in distal leaf axils; bracteoles attached 1–2.2 mm distal to base of ovary, linear-lanceolate or narrowly elliptic, 3–6.5(–7.2)× 0.3–1.5(–1.7) mm, apex acuminate, surfaces hirtellous. |
Flowers | sepals ovate-deltate, 10–20 × 7–12 mm, abruptly acuminate or acute, inconspicuously 5–7-nerved, surfaces strigillose; petals deep golden yellow, broadly obovate, 20–35 × 10–30 mm, apex shallowly emarginate, claw 1.5–3 mm; stamens 8 in 2 unequal series, filaments flattened and dilated near base, epipetalous set 3.4–4.5 mm, episepalous set 4.5–5.5 mm, anthers oblong, 4–5 mm; pollen shed in polyads; ovary subcylindric, slightly 4-angled, 8–12(–20) mm; nectary disc slightly elevated on ovary apex, 2–3 mm diam., 4-lobed, ringed by short hairs; style 3–3.5 mm, stigma clavate-capitate, 2.5–3 × 2–2.5 mm, often exserted beyond anthers. |
sepals ascending with reflexed tips, pale green abaxially, creamy white adaxially, often tinged with pink or red, ovate-deltate, 3.5–5.5(–6) × 2–4 mm, margins entire, apex elongate-acuminate to subcuspidate, surfaces densely hirtellous; petals 0; filaments yellowish, 1.5–2.5 mm, base dilated, anthers 0.6–0.9(–1.3) × 0.5–0.7 mm; pollen shed in tetrads; ovary obovoid to cup-shaped, 2.5–4 × 2.5–4 mm; nectary disc elevated 0.3–0.7 mm on ovary apex, bright yellow, turning black upon drying, 2–3.6 mm diam., indistinctly 4-lobed, densely hirtellous around style base and between lobes; style cream, 1–2 mm, sparsely to densely hirtellous, especially proximally, stigma capitate, 0.3–0.6 × 0.3–0.6 mm, not exserted beyond anthers. |
Capsules | clavate-cylindric, subterete to obtusely 4-angled, 20–35 × 3.5–5 mm, thin walls, irregularly dehiscent, tapering to pedicel 10–40 mm. |
subglobose or, sometimes, oblong-obovoid, subterete or with 4 rounded corners, 3–5 × 3–4.5 mm, hard-walled, irregularly dehiscent, pedicel 0–1 mm. |
Seeds | in several indistinct rows per locule, yellow-brown, oblong (appearing round), 0.5 mm, shiny, raphe 2/3 as wide as body. |
brown, elliptic-oblong or oblong-ovoid, slightly curved on both ends, 0.5–0.7 × 0.3–0.4 mm, surface cells ± isodiametric. |
2n | = 16. |
= 32. |
Ludwigia bonariensis |
Ludwigia pilosa |
|
Phenology | Flowering summer. | Flowering Jun–Sep. |
Habitat | Wet places, mainly along coastal areas, especially ditches, banks near brackish water. | Roadside ditches, marshes, swales in sandy pine flats, edges of pocosins, peaty bogs, low grassy savannas, swamp forests. |
Elevation | 0–200[–2600] m. (0–700[–8500] ft.) | 0–300 m. (0–1000 ft.) |
Distribution |
AL; FL; MS; NC; SC; TX; Mexico (Chihuahua, Durango, Puebla, Quintana Roo, Tabasco, Tamaulipas, Veracruz); South America (Argentina, Bolivia, Brazil, Paraguay, Uruguay)
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AL; FL; GA; LA; MS; NC; SC; TX; VA
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Discussion | The distribution of Ludwigia pilosa is nearly continuous along the Atlantic and Gulf coastal plains, from extreme southeastern Virginia to northern Florida, and west to Louisiana and southeastern Texas. Disjunct populations occur in northern Alabama and central North Carolina. Ludwigia pilosa is easily distinguished from most others in sect. Isnardia by being densely hirtellous throughout. Its showy sepals and nectary disc attract multiple insect visitors including ants, bumblebees, honeybees, moths, and wasps (C. I. Peng 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 | Jussiaea bonariensis, J. neglecta, J. suffruticosa var. bonariensis | Isnardia mollis, I. pilosa, L. hirsuta, L. mollis, L. rudis |
Name authority | (Micheli) H. Hara: J. Jap. Bot. 28: 291. (1953) | Walter: Fl. Carol., 89. (1788) |
Web links |