Ludwigia linifolia |
Ludwigia microcarpa |
|
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flaxleaf seedbox, southeastern primrose-willow |
smallfruit primrose-willow |
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Habit | Herbs slender, rarely with aerenchyma, forming slender stolons 4–15(–30) cm, 0.7–1(–1.5) mm thick. | 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 or ascending, slightly ridged, usually well branched, 12–55(–62) cm, glabrous. |
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 | alternate; stipules narrowly ovate to narrowly lanceolate, 0.2–0.3 × 0.1–0.2 mm; stolons: petiole narrowly attenuate, 0.05–0.5 cm, blade narrowly obovate or oblanceolate to spatulate, 0.5–2 × 0.1–0.6 cm; stems: sessile, blade linear to linear-oblanceolate, 1.5–4 × 0.1–0.4(–0.6) cm, base very narrowly cuneate, margins entire with obscure hydathodal glands, apex acuminate to acute; bracts linear, reduced. |
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 | leafy spikes, flowers solitary in leaf axils; bracteoles attached 0–1.5 mm distal to base of ovary, very narrowly oblanceolate to linear, (1.5–)2.5–9(–13) × 0.2–0.8 mm, margins entire, apex acute. |
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 ascending, green, narrowly lanceolate-deltate, (3–)4–7 × 1.1–1.7 mm, margins entire, apex narrowly acute, surfaces glabrous or minutely papillose; petals narrowly obovate-elliptic, 4–6 × 2–4 mm, base obtuse, apex obtuse or rounded; filaments pale yellow, (1.3–)1.5–2.5(–3) mm, anthers oblong, 0.6–1.1 × 0.5–0.8 mm; pollen shed in tetrads; ovary subcylindric, 3–4 × 1–1.5 mm; nectary disc elevated 0.3–0.7 mm on ovary apex, bright yellow, 0.8–1.5 mm diam., prominently 4-lobed, minutely papillose; style yellow, 1.25–2.5 mm, glabrous, stigma subcapitate, 0.3–0.6 × 0.6–0.8 mm, shallowly 4-lobed, not 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 | subcylindric, terete or slightly angled, 5–10(–12) ×1.3–2(–2.2) mm, hard-walled, irregularly dehiscent, pedicel 0 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 | reddish brown, oblong-elliptic, 0.6–0.7 × 0.2–0.3 mm, surface cells nearly isodiametric. |
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 linifolia |
Ludwigia microcarpa |
|
Phenology | Flowering late Jun–Oct. | Flowering Mar–Nov (year-round). |
Habitat | Drainage ditches, margins of creeks or swamps, open edges of cypress swamps, moist pinelands, edges of brackish lakes. | 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 | 0–300 m. (0–1000 ft.) | 0–400 m. (0–1300 ft.) |
Distribution |
AL; FL; GA; MS; NC; SC; Mexico (Tabasco) |
AL; AR; FL; GA; LA; MO; MS; NC; SC; TN; TX; VA; West Indies (Bahamas, Cuba, Jamaica)
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Discussion | Ludwigia linifolia is primarily a coastal species that extends farther inland in Georgia and the Carolinas. Being one of five diploids in sect. Isnardia, it has particularly prominent nectary lobes and appears to be modally outcrossing (C. I. Peng 1989). It also is known from a disjunct population on the Yucatán Peninsula in Tabasco, Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Isnardia linifolia | Isnardia microcarpa |
Name authority | Poiret in J. Lamarck et al.: Encycl., Suppl. 3: 513. (1814) | Michaux: Fl. Bor.-Amer. 1: 88. (1803) |
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