Ludwigia ravenii
Ludwigia grandiflora
Raven's primrose-willow
large-flower primrose-willow, Uruguayan primrose-willow
erect, slightly ridged, usually well branched, (15–)35–90 cm, densely hirtellous.
erect or ascending to creeping or floating, terete or sometimes angled distally, 20–300(–450) cm, usually densely branched, sometimes simple, glabrous if floating, or densely villous and viscid throughout, or rarely just on inflorescence.
alternate;
stipules lanceolate to broadly deltate, 0.2–0.5 × 0.1–0.3 mm;
stolons: petiole 0.1–0.3 cm, blade elliptic to orbiculate, 1–1.8 × 0.6–1.4 cm, base attenuate, apex rounded to acute;
stems: petiole narrowly winged, 0.1–0.8 cm, blade narrowly lanceolate-elliptic, 1.3–6.5 × 0.4–1.5 cm, base attenuate, margins entire with minute hydathodal glands, apex acute, surfaces densely hirtellous;
bracts not much reduced.
stipules (rarely in clusters of 3), ovate-deltate, 0.6–2 × 0.6–1.5 mm, fleshy, apex subacute, often mucronate;
petiole 0.1–1.1 cm;
blade usually lanceolate to (narrowly) elliptic or oblanceolate, rarely narrowly obovate, (1.7–)3.1–8(–10.5) × 0.5–2(–2.5) cm, chartaceous, viscid, base cuneate or attenuate, margins entire, apex obtuse or acute, always glandular-mucronate, surfaces densely villous, sometimes less dense adaxially, distal leaves more pubescent than proximal ones;
bracts scarcely reduced.
leafy racemes, flowers solitary in leaf axils;
bracteoles attached near base of ovary, lanceolate or elliptic to narrowly so, (1.5–)2–4.3 ×0.3–0.9 mm, apex acuminate, surfaces hirtellous.
on emergent stems sometimes in leafy racemes, flowers solitary in leaf axils;
bracteoles narrowly to broadly obovate, 1–1.2 × 0.7–0.8 mm, succulent, apex acute, oppositely attached at ovary base.
sepals ascending-spreading, green, broadly ovate-deltate, 1.5–3 × 1.4–2.1 mm, margins entire, apex acuminate, surfaces densely hirtellous;
petals 0;
filaments light green, 0.7–1.1 mm, anthers 0.3–0.4 × 0.4–0.5 mm;
pollen shed in tetrads;
ovary obovoid to obconic, 2.8–3.5 × 2–3 mm;
nectary disc elevated 0.3–0.4 mm on ovary apex, light green, 1.4–2.5 mm diam., 4-lobed, glabrous;
style light green, 0.3–0.5 mm, glabrous, stigma clavate to subcapitate, 0.4–0.6 × 0.3–0.5 mm, not exserted beyond anthers.
sepals usually deciduous, not persistent on capsule, lanceolate, 6–12(–16) × 2–4 mm, chartaceous, apex acute, surfaces densely villous;
petals yellow, fan-shaped, (12–)16–20(–26) × 11–16(–21) mm, apex rounded, usually emarginate, rarely mucronate;
stamens 10(or 12), in 2 unequal series, yellow, filaments reflexed, shorter ones (2.8–)3.8–5.3 mm, longer ones (3.7–)6–6.5 mm, anthers oblong, 1–2.5 × (0.6–)0.8–1.2 mm;
ovary subcylindric, terete, 6–12 × 1.5–2.5 mm, apex thickened, densely villous;
nectary disc slightly raised on ovary apex, yellow, 1.5–2.5 mm diam., lobed, ringed with villous hairs;
style yellow, 4.7–6.7(–8) mm, glabrous or sparsely pubescent near base, stigma subcapitate-globose, 1–1.3 × 1.6–2.5 mm, usually exserted beyond anthers.
oblong-obovoid, subterete to scarcely 4-angled, (3–)4–5(–5.3) × 2.5–3.5(–4) mm, hard-walled, irregularly dehiscent, pedicel 0.2–0.5 mm.
subcylindric, terete, straight or curved, (11–)14–25 × 3–4 mm, with thick woody walls, irregularly and tardily dehiscent, villous-viscid, pedicel 13–25(–27) mm.
light brown, elliptic-oblong with slightly curved ends, 0.5–0.7 ×0.3–0.4 mm, surface cells elongate transversely to seed length.
embedded in wedge-shaped piece of endocarp, 0.8–1 × 0.8–0.9 mm.
= 32.
= 48.
Ludwigia ravenii
Ludwigia grandiflora
Ludwigia ravenii is an uncommon species occurring in scattered populations in coastal southeastern Virginia and eastern North Carolina, with single disjunct populations in southeastern South Carolina and northeastern Florida. C. I. Peng (1989) observed its similarity to L. pilosa by virtue of its dense, hirtellous pubescence, but noted its smaller, more consistently autogamous flowers. It is in the Center for Plant Conservation’s National Collection of Endangered Plants.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Ludwigia grandiflora occurs in two disjunct areas: the southeastern United States on the coastal plain of southern South Carolina, Georgia, northern Florida, Louisiana, west to central Texas, and recently in southern California (P. C. Hoch and B. J. Grewell 2012) and Oregon; and central South America from south of the Amazon basin of Brazil and Bolivia where it is very scattered, to Uruguay, northeastern Argentina, and Paraguay where it is very frequent. It has been collected three times in Guatemala and twice in Missouri, although it is not clearly established in either region. It usually grows below 200 m elevation, but in Guatemala and in Santa Catarina, Brazil (Smith & , MO), it has been collected as high as Klein 133831200 m elevation. Populations of L. grandiflora in the United States are fairly variable, although not as much as in South American populations.
As noted by Greuter and Burdet, the publication of Jussiaea grandiflora Ruíz & Pavon, which was a synonym of J. peruviana, occurred in 1830, not in 1802 as reported (P. A. Munz 1942; P. H. Raven 1963[1964]). Therefore, J. grandiflora Michaux in 1803 is legitimate, and J. grandiflora Ruíz & Pavon is an illegitimate homonym.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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