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false loosestrife, many-fruit water-primrose, manyfruit primrose-willow

yerba de jicotea

Habit Herbs slender, with well-developed aerenchyma on submerged stems, forming stolons 2.5–15(–22) cm, 1–2.3 mm thick, well branched. Herbs annual, rarely persistent a second year from woody base.
Stems

erect or ascending, slightly ridged, well branched, (10–)25–60(–85) cm, glabrate with raised ± strigillose lines decurrent from leaf axils.

erect, 4-angled, rarely 4-winged, sometimes basally terete, 40–280 cm, simple to densely branched, branches often ascending, glabrous.

Leaves

alternate;

stipules narrowly to broadly ovate, 0.1–0.4 × 0.1–0.3 mm;

stolons: leaves often clustered near apex of stolon, petiole 0–0.5 cm, blade narrowly elliptic or oblanceolate, 0.8–2(–3.2) × 0.2–0.8(–1.2) cm, base attenuate, margins entire or remotely denticulate, apex acute, surfaces glabrous;

stems: petiole winged, 0.1–1 cm, blade very narrowly oblong-elliptic, 3.5–11 × 0.4–1(–1.7) cm, base very narrowly cuneate or long-attenuate, margins entire and densely, minutely papillose-serrulate with obscure hydathodal glands, apex narrowly acute or acuminate, surfaces glabrous;

bracts not much reduced.

stipules deltate, 0.2–0.3 × 0.15–0.2 mm;

petiole 0.2–2.2 cm, somewhat flattened and continuous with ridges or wings on stem;

blade elliptic to narrowly lanceolate, 2–20 × 0.2–4 cm, base cuneate, margins minutely scabrid, apex acute or acuminate, membranous, surfaces glabrous or sometimes minutely strigillose along abaxial veins;

bracts often reduced.

Inflorescences

elongated, leafy spikes, flowers solitary in leaf axils, sometimes borne almost to base of stems;

bracteoles attached 0.5–2.5(–3) mm distal to base of ovary, linear-lanceolate, 3.5–6.5(–8) × 0.

leafy spikes, flowers solitary in distal axils;

bracteoles attached at base of ovary or on lower 1/2, without subtending glands, deltate, 0.3–0.5 × 0.2–0.3 mm, apex acute.

Flowers

sepals spreading horizontally with reflexed tips, pale green, narrowly ovate-deltate, 2.5–4.5 × 1.5–3.2 mm, margins entire, minutely papillose-serrulate, apex elongate-acuminate, surfaces glabrous;

petals 0;

filaments yellowish green, 0.7–1.5 mm, base dilated, anthers 0.5–0.9 × 0.5–0.7 mm;

pollen shed in tetrads;

ovary oblong, barely 4-angled, 3–4.5 × 2–3.5 mm;

nectary disc elevated 0.5–0.8 mm on ovary apex, yellowish green, 1.8–3 mm diam., 4-lobed, glabrous;

style yellowish green, 0.5–0.8 mm, glabrous, stigma broadly clavate to subglobose, 0.4–0.8 × 0.3–0.6 mm, usually 4-lobed, not exserted beyond anthers.

sepals ovate or lanceolate, 3–6 × 1–2 mm, apex acute or short-acuminate, surfaces usually glabrous, sometimes strigillose;

petals obovate, 3.5–5 × 2–2.5 mm;

stamens 8 in 2 subequal series, filaments 1.3–1.5 mm, anthers oblong, 0.6–1 × 0.4–0.5 mm;

ovary obconic, 4-angled, 4–10 × 2–4 mm, usually glabrous, rarely strigillose;

nectary disc plane on ovary apex, 3–4 mm diam., 4-lobed, glabrate;

style 0.5–1.5 × 0.5–0.6 mm, stigma globose, 0.8–1 × 1–1.2 mm, not exserted beyond anthers and pollen shed directly on it.

Capsules

oblong-obovoid, obscurely 4-angled, 4–7 × 2.5–5 mm, hard-walled, irregularly dehiscent, pedicel 0.1–0.3 mm.

oblong-linear to squarish-cylindric, 4-angled, 10–22 × 2–4 mm, thin-walled, irregularly dehiscent, subsessile.

Seeds

light brown, narrowly oblong with curved ends, 0.5–0.6 × 0.2–0.3 mm, surface cells elongate parallel to seed length.

elongate-ovoid, 0.3–0.5 × 0.2–0.3 mm, raphevery reduced and inconspicuous.

4

–1(–1.3) mm, with a swollen base, margins minutely papillose-serrulate.

2n

= 32.

= 16.

Ludwigia polycarpa

Ludwigia erecta

Phenology Flowering Jun–Sep. Flowering summer–early fall.
Habitat Ditches, moist prairies, alluvial ground of ponds, lakes, and rivers, marshes, swales, edges of lagoons, low fallow fields. Pond margins and depressions, wet sand ditches and prairies.
Elevation 100–300 m. (300–1000 ft.) 0–100[–300] m. (0–300[–1000] ft.)
Distribution
from FNA
CT; IA; ID; IL; IN; KS; KY; MA; MI; MN; MO; NE; OH; PA; VA; WI; WV; ON
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AZ; FL; Central America; South America; Mexico (Campeche, Chiapas, Jalisco, Michoacán, Nayarit, Oaxaca, Tabasco); West Indies; Africa (Nigeria, Tanzania); Indian Ocean Islands (Comoros Islands, Madagascar, Seychelles)
[BONAP county map]
Discussion

Ludwigia polycarpa, unlike all other species in sect. Isnardia, is distributed primarily in the central Midwest and Great Lakes regions, with one highly disjunct population recorded from Kootenai County, Idaho, which is presumably introduced. This species has also been found scattered as far east as Connecticut and Massachusetts, and reports of it from Arkansas, Maine, Tennessee, and Vermont cannot be confirmed. As indicated by C. I. Peng (1989), a report of this species from Alabama involved a natural hybrid between L. glandulosa and L. pilosa.

The basal stolons formed by Ludwigia polycarpa tend to be shorter, more condensed, and more branched than those found in other species, and may be a morphological adaptation to perennial survival in the colder areas in which it grows.

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

Ludwigia erecta, which is morphologically similar to L. decurrens and often growing with it, is modally self-pollinating and is usually easy to distinguish from that species.

Although Ludwigia erecta is widely distributed in warm temperate regions in the New World and Africa, it appears to be most closely related to species restricted to South America. Its appearance in a rather remote locality in Arizona in 2006 may be attributable to transport there in mud on migrating birds.

(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. curtissii, 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. 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. 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 Isnardia polycarpa Jussiaea erecta, Isnardia discolor, J. acuminata, J. acuminata var. latifolia, J. acuminata var. longifolia, J. altissima, J. declinata, J. erecta var. plumeriana, J. erecta var. sebana, J. onagra, J. plumeriana, J. ramosa, L. acuminata
Name authority Short & R. Peter: Transylvania J. Med. Assoc. Sci. 8: 581. (1835) (Linnaeus) H. Hara: J. Jap. Bot. 28: 292. (1953)
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