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Curtiss' primrose-willow

wingleaf primrose-willow

Habit Herbs rarely creeping and rooting at nodes, stolons usually absent. Herbs annual or short-lived perennial, roots and lower stem sometimes inflated and spongy.
Stems

erect or ascending at base, very rarely prostrate, unbranched to well branched, branches sometimes very slender, 15–75 cm, glabrous, with slightly raised lines decurrent from leaf axils.

erect or strongly ascending, sharply 4-angled and 4-winged, 30–200 cm, simple to densely branched, glabrous.

Leaves

alternate;

stipules reddish purple, narrowly ovate, 0.2–0.3 × 0.1–0.3 mm, succulent;

petiole winged, 0.3–1.2 cm, blade usually oblanceolate-spatulate to spatulate or oblanceolate, rarely sublinear, 1–2.5(–3) × 0.1–0.8 cm, base attenuate, margins subentire with hydathodal glands, apex acute or mucronate, surfaces glabrous;

bracts not reduced.

stipules deltate, 0.4–0.5 × 0.2 mm;

sessile and continuous with wings on stem;

blade lanceolate or narrowly lanceolate to narrowly ovate or elliptic, 2–20 × 0.2–5 cm, base acute or rounded, margins entire, often minutely scabrid, apex acute or acuminate, membranous, surfaces glabrous or sometimes minutely puberulent on abaxial veins;

bracts linear, mostly reduced.

Inflorescences

usually not congested, leafy racemes or spikes, flowers solitary in leaf axils;

bracteoles attached in opposite pairs near base of ovary, narrowly lanceolate, lanceolate-elliptic, or oblong-linear, 1.5–3.5(–4) × 0.4–0.8 mm, swollen at base, apex acuminate.

open, leafy racemes, flowers solitary in distal axils;

bracteoles deciduous, usually attached near base of ovary, without subtending glands, lanceolate to subovate, 0.5–1 × 0.2–0.5 mm, apex acute.

Flowers

sepals ascending, green fading to white near base, ovate-deltate, 1.5–3 × 1.2–2 mm, margins entire, apex narrowly acute or acuminate, surfaces glabrous;

petals 0(–3), narrowly elliptic or spatulate, 1–2.5 × 0.5–1 mm, base attenuate, apex obtuse;

filaments pale yellow, 0.8–1(–1.3) mm, anthers 0.3–0.6 × 0.3–0.5 mm;

pollen shed singly;

ovary obovate-obpyramidal, 2–2.5 × 1.8–2.3 mm, glabrous;

nectary disc elevated 0.3–0.4 mm on ovary apex, green, 0.9–1.6 mm diam., prominently 4-lobed, glabrous;

style pale green, 0.4–0.7 mm, glabrous, stigma pale yellow, subglobose, 0.3–0.4 × 0.2–0.4 mm, not exserted beyond anthers.

sepals ovate to lanceolate, 7–12 × 1.5–4 mm, apex acute or short acuminate, membranous, margins usually minutely scabrid, surfaces usually glabrous, sometimes puberulent abaxially;

petals orbiculate-obovate, 10–20 × 10–18 mm, short-clawed;

stamens 8 in 2 subequal series, yellow, filaments 1.3–2.5 mm, anthers oblong, 1.3–1.6 × 0.5–0.6 mm;

ovary obconic, sharply 4-angled and 4-winged, 6–10 × 2–4.5 mm, glabrous or minutely puberulent;

nectary disc plane on ovary apex, 3–5 mm diam., 4-lobed, glabrate or ringed with short hairs;

style 2.5–3.2 × 0.5–0.6 mm, stigma globose, 1–2 × 1–2 mm, not exserted beyond anthers and pollen shed directly on it.

Capsules

obconic, obscurely 4-angled, (2–)2.5–4(–4.7) × 2–3(–3.5) mm, hard-walled, dehiscent by loculicidal slits, pedicel 0.1–0.5 mm.

rarely sharply curved, subclavate to oblong-obovoid or narrowly obpyramidal, sharply 4-angled and 4-winged, 10–25 × 3–5 mm, glabrous, pedicel 2–15 mm.

Seeds

light brown, ellipsoid, 0.4–0.6 × 0.3–0.4 mm, surface cells transversely elongate, glabrous or, sometimes, with surface wax that mimics appressed hairs.

oblong or subcylindric, 0.5–0.6 × 0.2 mm, striate, raphe very narrow and inconspicuous.

2n

= 64.

= 16.

Ludwigia curtissii

Ludwigia decurrens

Phenology Flowering Mar–Nov (year-round). Flowering summer–early fall.
Habitat Pine savannas and flatwoods, marshes, edges of ponds and streams, sandy or peaty swales, limestone prairies, solution pits on limestone. Moist or swampy habitats along sloughs, muddy stream banks, marshy shores of lakes and ponds, ditches, swamps.
Elevation 0–50 m. (0–200 ft.) 0–300[–600] m. (0–1000[–2000] ft.)
Distribution
from FNA
FL; West Indies (Bahamas)
[BONAP county map]
from FNA
AL; AR; DC; FL; GA; IL; KY; LA; MD; MO; MS; NC; OH; OK; PA; SC; TN; TX; VA; WI; WV; Central America; South America; Mexico (Campeche, Chiapas, Michoacán, Tabasco); West Indies; Bermuda [Introduced in Europe (France), e Asia (Japan), Africa (Cameroon), Pacific Islands (Philippines)]
[WildflowerSearch map]
[BONAP county map]
Discussion

Ludwigia curtissii is the only octoploid (n = 32) in sect. Isnardia, and is restricted to peninsular Florida and the Bahamas. It and L. simpsonii they are the only members of the section that do not form true stolons; instead they simply sprout new shoots from the base. The two species are similar in many ways and appear to share three genomes (C. I. Peng 1988).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Ludwigia decurrens appears to be most closely related to L. erecta, differing by having winged, not angled, capsules and larger flowers, with sepals 7–12 mm and petals 10–20 mm (in L. erecta, sepals 3–6 mm, petals 3.5–5 mm). They often grow in close proximity and may hybridize, but hybrids would be difficult to detect. Ludwigia decurrens is often self-pollinating, but larger flowers may promote outcrossing.

Ludwigia jussiaeoides Michaux is an illegitimate later homonym of L. jussiaeoides Desrousseaux and pertains here.

(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. Pterocaulon
Sibling taxa
L. alata, L. alternifolia, L. arcuata, L. bonariensis, L. brevipes, L. decurrens, L. erecta, L. glandulosa, L. grandiflora, 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
L. alata, L. alternifolia, L. arcuata, L. bonariensis, L. brevipes, L. curtissii, L. erecta, L. glandulosa, L. grandiflora, 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 L. spathulifolia Diplandra decurrens, D. montana, Jussiaea alata, J. bertonii, J. decurrens, J. palustris, J. pterophora, J. tenuifolia
Name authority Chapman: Fl. South. U.S. ed. 2, 621. (1883) Walter: Fl. Carol., 89. (1788)
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