Ludwigia sphaerocarpa |
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globefruit primrose-willow, round-pod water-primrose |
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Habit | Herbs often with prominent aerenchyma when base submerged, forming stolons 20–90 cm, 2–3.5 mm thick, floating, sometimes branched. |
Stems | erect, slightly ridged, well branched, (40–)60–110 cm, densely strigillose or glabrous. |
Leaves | alternate; stipules lanceolate-deltate, 0.1–0.4 × 0.1–0.2 mm; stolons: petiole ± winged, 0.1–0.3 cm, blade narrowly elliptic to oblanceolate or spatulate, 0.9–3 × 0.4–0.8(–1.3) cm, base attenuate, margins subentire with hydathodal glands, apex acute or obtuse; stems: petiole 0.1–0.4(–1) cm, blade narrowly elliptic or lanceolate to sublinear, on main stem (2.6–)6–10 × 0.5–1.1(–1.6) cm, on branches 2–5(–6) × 0.3–0.5(–0.6) cm, base attenuate or narrowly cuneate, margins entire with hydathodal glands mainly on primary cauline leaves, apex acute to very narrowly acute, surfaces glabrous or densely strigillose; bracts not much reduced. |
Inflorescences | open, leafy racemes, more congested on branches, flowers solitary in leaf axils; bracteoles attached in subopposite pairs near base of ovary, usually linear to very narrowly lanceolate, rarely lanceolate, 0.5–1.5 × 0.1–0.3 mm, apex acuminate. |
Flowers | sepals ascending, yellow or cream adaxially, ovate-deltate, 2–3.5(–4) × 1.6–3(–3.3) mm, margins entire, apex acuminate, surfaces glabrous or densely strigillose; petals 0; filaments yellow, 1–1.7 mm, slightly dilated toward base, anthers 0.5–0.8 × 0.4–0.7 mm; pollen shed in tetrads; ovary broadly obovoid or cup-shaped, 1.5–3.5 × 2–3 mm; nectary disc elevated 0.4–0.6 mm on ovary apex, bright yellow, 1.5–3 mm diam., 4-lobed, glabrous or short-hirtellous between lobes; style yellow, 0.6–1(–1.3) mm, glabrous or strigillose proximally, stigma yellow, capitate to subglobose, 0.3–0.5 × 0.4–0.7 mm, not exserted beyond anthers. |
Capsules | sometimes tinged pink, subglobose, subterete, 2–4(–4.5) × 2–4 mm, hard-walled, irregularly dehiscent, pedicel 0.5–1.2(–2.3) mm. |
Seeds | brown to light brown, elliptic, 0.4–0.7 × 0.3–0.4 mm, surface cells transversely elongate to seed length, sometimes oblique. |
2n | = 32. |
Ludwigia sphaerocarpa |
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Phenology | Flowering Jun–Sep. |
Habitat | Drainage ditches, shores of slow-moving streams or ponds, marshes, swales, swamp forests, edges of limestone sinks, peaty bogs in pastures, interdunal marshes. |
Elevation | 0–300 m. (0–1000 ft.) |
Distribution |
AL; CT; DE; FL; GA; IL; IN; LA; MA; MD; MI; MS; NC; NJ; NY; PA; RI; SC; TN; TX; VA
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Discussion | Ludwigia sphaerocarpa has its primary distribution along the Atlantic coastal plain, from Massachusetts to north-central Florida, and west along the Gulf coastal plain sporadically to southeastern Texas. Disjunct populations occur in south-central Tennessee, extreme southwestern Indiana, along Lake Michigan in northeastern Illinois and northwestern Indiana, and in west-central New York. In Michigan, L. sphaerocarpa is known from Allegan and Berrien counties, as reported by Reznicek and Voss in the Michigan Flora (https://michiganflora.net/species.aspx?id=1757). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. |
Parent taxa | |
Sibling taxa | |
Synonyms | Isnardia sphaerocarpa, L. sphaerocarpa var. deamii, L. sphaerocarpa var. jungens, L. sphaerocarpa var. macrocarpa |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 213. (1817) |
Web links |