Ludwigia virgata |
Ludwigia microcarpa |
|
---|---|---|
savannah primrose-willow |
smallfruit primrose-willow |
|
Habit | 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. | |
Roots | fascicled, often fusiform, or spreading horizontally. |
|
Stems | 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. |
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, 0.1–0.2 × 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. |
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 | 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. |
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 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. |
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 | subglobose to ellipsoid, 3.5–6.8 × 3.3–4.3 mm, 4-angled, angles not developed into wings, pedicel 6.5–17 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 | 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. |
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 virgata |
Ludwigia microcarpa |
|
Phenology | Flowering summer. | Flowering Mar–Nov (year-round). |
Habitat | Sandy savannas, pinelands, damp roadside ditches, margins of ponds, bogs, irrigated fields, usually within 75 miles of sea coast. | 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; VA
|
AL; AR; FL; GA; LA; MO; MS; NC; SC; TN; TX; VA; West Indies (Bahamas, Cuba, Jamaica)
|
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.) |
|
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Ludwigia | Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Isnardia |
Sibling taxa | ||
Synonyms | Isnardia virgata | Isnardia microcarpa |
Name authority | Michaux: Fl. Bor.-Amer. 1: 89. (1803) | Michaux: Fl. Bor.-Amer. 1: 88. (1803) |
Web links |