Ludwigia lanceolata |
Ludwigia alternifolia |
|
---|---|---|
lanceleaf primrose-willow |
bushy seedbox, ludwigie à feuilles alternes, rattlebox, seedbox, square-pod water-primrose |
|
Habit | Herbs slender, with well-developed aerenchyma when base submerged, often forming stolons 10–40 cm, 2–3 mm thick, stolons with widely spaced leaves. | |
Roots | fusiform, fascicled, thickened, epidermis splitting or peeling near base. |
|
Stems | erect, subterete or slightly ridged, well branched distally, 45–100 cm, glabrous, with raisedlines decurrent from leaf axils. |
subterete or somewhat angled, with narrow raised lines or wings decurrent from leaf axils, 40–150 cm, well branched in distal 1/2, glabrous or sparsely to densely strigillose. |
Leaves | alternate; stipules ovate to very broadly ovate, 0.2–0.5 ×0.1–0.3 mm, succulent; stolons: petiole winged, 0.2–1 cm, blade orbiculate or elliptic to broadly elliptic, 0.5–2.7 × 0.6–1.2 cm, base attenuate, apex rounded to acute; main stem: petiole winged, 0.1–0.5 cm, blade elliptic, oblanceolate, or narrowly oblanceolate to sublinear, 2–7.5 × 0.2–0.8(–1.4) cm, base narrowly cuneate, sometimes attenuate, margins entire with minute hydathodal glands, apex acute to narrowly acute, leaves on side branches much reduced; bracts sublinear, moderately reduced. |
stipules narrowly deltate, 0.05–0.2 × 0.05–0.1 mm; petiole 0.1–0.3(–0.7) cm; blade lanceolate-elliptic, (0.6–)2–12 × (0.3–)1–1.5(–2.5) cm, base attenuate, margins entire, apex acute, surfaces strigillose throughout or glabrate with strigillose veins; bracts often reduced and more linear. |
Inflorescences | open spikes, flowers solitary in distal leaf axils; bracteoles attached in opposite pairs at or slightly distal to base of ovary, ovate-elliptic to very narrowly elliptic, 1.5–4.3 × 0.4–1.4 mm, often with a swollen base, margins minutely papillose, apex subacute. |
leafy racemes, flowers solitary in leaf axils; bracteoles linear-lanceolate, 1–2.5 mm, margins entire, apex acute or subacuminate, glabrous or with scattered hairs, attached near base of ovary. |
Flowers | sepals ascending, pale green, broadly ovate-deltate, 1.5–2.5 × 1.8–3.3 mm, margins minutely papillose, apex usually acute, rarely acuminate, surfaces glabrous; petals 0; filaments nearly translucent, 1–1.4 mm, base dilated, anthers 0.4–0.6(–0.8) × 0.5–0.6 mm; pollen shed in tetrads; ovary broadly obovoid or cup-shaped, 2.5–3.5 × 2.2–3.2 mm; nectary disc elevated 0.4–0.6 mm on ovary apex, yellowish green, 1.8–2.6 mm diam., 4-lobed, glabrous; style yellowish green, 0.5–0.7 mm, glabrous, stigma yellowish green, broadly capitate to subglobose, 0.3–0.5 × 0.7–1 mm, not exserted beyond anthers. |
sepals narrowly ovate-deltate, (6–)6.5–9.5 × 4–6.5 mm, margins entire, apex acute to obtuse, surfaces strigillose, sometimes mixed with villous hairs, or glabrate; petals cordate, 10–14 ×8–12 mm, base attenuate, apex emarginate; filaments opaque white, awl-shaped, 1–3 mm, anthers 1–1.7 × 0.6–0.8 mm; ovary subcuboid to globose, 2.5–4 ×2.5–3.5 mm; nectary disc slightly elevated on ovary apex, 0.8–1.5 mm diam., 4-lobed, ringed with soft, curly hairs or glabrous; style 1.5–2.4 mm, glabrous, stigma light yellow, capitate to hemispherical, 1–1.3 × 1.4–2 mm, shallowly 4-lobed, not or scarcely exserted beyond anthers. |
Capsules | obpyramidal, sharply 4-angled and 4-winged, wings 0.3–0.7mm wide, 3.5–5 × 2.5–4.5 mm, hard-walled, dehiscent by apical ring, pedicel 0.1–0.5 mm. |
subcuboid to squarish globose, 4–6(–7) × 4–6 mm, 4-angled and 4-winged, wings 0.3–1.5 mm wide, pedicel 2–7 mm. |
Seeds | light brown, narrowly oblong with constricted ends, 0.6–0.8 ×0.2–0.3 mm, surface cells nearly isodiametric. |
light brown, oblong to reniform, 0.5–0.8 × 0.2–0.4 mm, surface cells elongate transversely to seed length. |
2n | = 32. |
= 16. |
Ludwigia lanceolata |
Ludwigia alternifolia |
|
Phenology | Flowering Jun–Oct. | Flowering summer–early fall. |
Habitat | Ditches, low meadows, cypress swamps, moist pinelands, edges of pocosins, sandy peaty soil. | Swamps, damp, peaty places, roadside ditches, margins of cultivated fields. |
Elevation | 0–100 m. (0–300 ft.) | 0–1800 m. (0–5900 ft.) |
Distribution |
FL; GA; NC; SC
|
AL; AR; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WI; WV; ON; QC
|
Discussion | Ludwigia lanceolata is fairly uncommon, with scattered populations occurring along the Atlantic coast of southern North Carolina, South Carolina, eastern and southern Georgia, and peninsular Florida. It reaches its western limit in the central panhandle of Florida. C. I. Peng (1988, 1989) found this tetraploid species to be interfertile with other tetraploid species in the section, but few natural hybrids are found, perhaps due to persistent autogamy and habitat specialization. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Ludwigia alternifolia is widespread and common in the eastern half of the flora area, as far west as Ontario in Canada, eastern Colorado, and Texas. Ludwigia macrocarpa Michaux 1803 is a superfluous, illegitimate name for L. alternifolia. Rhexia linearifolia Poiret was originally described as a species of Melastomataceae, but the description is superficially similar to Ludwigia and has often been included in synonymy with L. alternifolia. The type of R. linearifolia has not been located or studied. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Isnardia lanceolata | Isnardia alternifolia, I. alternifolia var. salicifolia, I. alternifolia var. uniflora, I. aurantiaca, L. alternifolia var. linearifolia, L. alternifolia var. pubescens, L. angustifolia var. ramosissima, L. aurantiaca, L. ramosissima, L. salicifolia, L. uniflora |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 213. (1817) | Linnaeus: Sp. Pl. 1: 118. (1753) |
Web links |