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flaxleaf seedbox, southeastern primrose-willow

large-flower primrose-willow, Uruguayan primrose-willow

Habit Herbs slender, rarely with aerenchyma, forming slender stolons 4–15(–30) cm, 0.7–1(–1.5) mm thick. Herbs, subshrubs, or emergent aquatics, rooting at lower nodes, sometimes woody at base, white pneumatophores 8–10 cm often on submerged stems.
Stems

erect or ascending, slightly ridged, usually well branched, 12–55(–62) cm, glabrous.

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.

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.

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.

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.

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.

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 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.

Capsules

subcylindric, terete or slightly angled, 5–10(–12) ×1.3–2(–2.2) mm, hard-walled, irregularly dehiscent, pedicel 0 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.

Seeds

reddish brown, oblong-elliptic, 0.6–0.7 × 0.2–0.3 mm, surface cells nearly isodiametric.

embedded in wedge-shaped piece of endocarp, 0.8–1 × 0.8–0.9 mm.

2n

= 16.

= 48.

Ludwigia linifolia

Ludwigia grandiflora

Phenology Flowering late Jun–Oct. Flowering summer.
Habitat Drainage ditches, margins of creeks or swamps, open edges of cypress swamps, moist pinelands, edges of brackish lakes. Wet places, along slow-moving rivers, streams, canals, ditches, often growing into main channel as aquatic weed.
Elevation 0–300 m. (0–1000 ft.) 0–200[–1200] m. (0–700[–3900] ft.)
Distribution
from FNA
AL; FL; GA; MS; NC; SC; Mexico (Tabasco)
[BONAP county map]
from FNA
AL; AR; CA; FL; GA; KY; LA; MO; MS; NC; NJ; NY; OK; OR; PA; SC; TN; TX; VA; WA; WV; Central America (Guatemala); South America (Argentina, Bolivia, Brazil, Paraguay, Uruguay)
[WildflowerSearch map]
[BONAP county map]
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.)

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.)

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Isnardia Onagraceae > subfam. Ludwigioideae > Ludwigia > sect. Jussiaea
Sibling taxa
L. alata, L. alternifolia, L. arcuata, L. bonariensis, L. brevipes, L. curtissii, L. decurrens, L. erecta, L. glandulosa, L. grandiflora, L. hexapetala, L. hirtella, L. lanceolata, L. leptocarpa, L. linearis, L. maritima, L. microcarpa, L. octovalvis, L. palustris, L. peploides, L. peruviana, L. pilosa, L. polycarpa, L. ravenii, L. repens, L. simpsonii, L. spathulata, L. sphaerocarpa, L. suffruticosa, L. virgata
L. alata, L. alternifolia, L. arcuata, L. bonariensis, L. brevipes, L. curtissii, L. decurrens, L. erecta, L. glandulosa, L. hexapetala, L. hirtella, L. lanceolata, L. leptocarpa, L. linearis, L. linifolia, L. maritima, L. microcarpa, L. octovalvis, L. palustris, L. peploides, L. peruviana, L. pilosa, L. polycarpa, L. ravenii, L. repens, L. simpsonii, L. spathulata, L. sphaerocarpa, L. suffruticosa, L. virgata
Synonyms Isnardia linifolia Jussiaea grandiflora, J. repens var. grandiflora, J. repens var. hispida, J. stenophylla, J. stuckertii, J. uruguayensis, L. clavellina var. grandiflora, L. uruguayensis
Name authority Poiret in J. Lamarck et al.: Encycl., Suppl. 3: 513. (1814) (Michaux) Greuter & Burdet: Willdenowia 16: 448. (1987)
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