Ludwigia bonariensis |
Ludwigia microcarpa |
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Carolina primrose-willow |
smallfruit primrose-willow |
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Habit | Herbs, from woody rootstock. | Herbs slender, sometimes suffrutescent from woody base, often with aerenchyma, rarely creeping and rooting at nodes, often forming slender stolons 4–15(–25) cm, 0.4–0.8 mm thick. |
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. |
usually erect or ascending, rarely prostrate, slightly to distinctly winged, wings to 1.8 mm wide, unbranched to densely branched, 5–60 cm, glabrous. |
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 lanceolate-deltate, 0.13–0.15 × 0.1–0.13 mm; stolons: petiole attenuate, 0.1–0.5 cm, blade broadly elliptic to suborbiculate, 0.2–0.7 × 0.2–0.5 cm; stems: petiole winged, 0.1–0.5 cm, blade obovate-spatulate or oblanceolate, sometimes narrowly oblanceolate-elliptic, 0.4–1.7 × 0.15–1 cm, base attenuate, margins subentire or often with hydathodal glands forming minute teeth, or minutely papillose-strigillose, apex acute or mucronate, surfaces glabrous; leaves on side branches much reduced, glabrous; bracts near apex and on branches 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. |
leafy spikes or racemes, flowers solitary in axils, usually not crowded; bracteoles attached at base of ovary, sublinear or narrowly oblong, 0.4–1.2(–1.5) × 0.1–0.4 mm, usually with swollen base. |
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 or spreading, pale green to cream adaxially, ovate-deltate, 0.9–2 × 1–1.9 mm, margins minutely papillose-strigillose or entire, apex acuminate, surfaces glabrous; petals 0; filaments translucent, 0.4–0.55 mm, anthers 0.1–0.2 × 0.2–0.3 mm; pollen shed singly; ovary pale green, obovoid-subglobose, 0.8–1 × 0.8–1.2 mm, glabrate; nectary disc nearly flat on ovary apex, light green, 0.5–1.2 mm diam., 4-lobed, glabrous; style light green, 0.3–0.6 mm, glabrous, stigma subcapitate, 0.15–0.3 × 0.05–0.15 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. |
obconic, subterete, 1–1.5 × 1.4–1.9 mm, thin-walled, seeds often visible as bumps, dehiscent by apical ring, pedicel 0–0.2 mm. |
Seeds | in several indistinct rows per locule, yellow-brown, oblong (appearing round), 0.5 mm, shiny, raphe 2/3 as wide as body. |
dark reddish brown, oblong-ovoid, 0.5–0.6 × 0.3–0.4 mm, surface cells transversely elongate, glabrous or, sometimes, densely covered by waxy hairs. |
2n | = 16. |
= 16. |
Ludwigia bonariensis |
Ludwigia microcarpa |
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Phenology | Flowering summer. | Flowering Mar–Nov (year-round). |
Habitat | Wet places, mainly along coastal areas, especially ditches, banks near brackish water. | Roadside ditches, marshes, borders of ponds and streams, low meadows, low areas in open woods, edges of swamp forests, brackish marshes, hammocks, solution pits of limestone on marl prairies. |
Elevation | 0–200[–2600] m. [0–700[–8500] ft.] | 0–400 m. [0–1300 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; AR; FL; GA; LA; MO; MS; NC; SC; TN; TX; VA; West Indies (Bahamas, Cuba, Jamaica)
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Discussion | The diploid Ludwigia microcarpa has the smallest stature, leaves, flowers, fruits, and fewest seeds (ca. 10–20) per capsule of any species in sect. Isnardia (C. I. Peng 1989). Most plants start to flower when young. (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 microcarpa |
Name authority | (Micheli) H. Hara: J. Jap. Bot. 28: 291. (1953) | Michaux: Fl. Bor.-Amer. 1: 88. (1803) |
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