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Ludwigia hexapetala
URUGUAYAN PRIMROSE-WILLOW

Higher Taxonomy
Family: OnagraceaeView DescriptionDichotomous Key

Common Name: EVENING-PRIMROSE FAMILY
Habit: Annual to perennial herb (to tree). Leaf: cauline or basal, alternate, opposite, or whorled, generally simple and toothed (to pinnately compound); stipules 0 or generally deciduous. Inflorescence: spike, raceme, panicle, or flowers 1 in axils; bracted. Flower: generally bisexual, generally radial, often opening at either dawn or dusk; hypanthium generally prolonged beyond ovary (measured from ovary tip to sepal base); sepals 4(2--7); petals 4(2--7, rarely 0), often fading darker; stamens 2 × or = sepals in number, anthers 2-chambered, opening lengthwise, pollen interconnected by threads; ovary inferior, chambers generally as many as sepals (sometimes becoming 1), placentas axile or parietal, ovules 1--many per chamber, style 1, stigma 4-lobed (or lobes as many as sepals), club-shaped, spheric, or hemispheric. Fruit: capsule, loculicidal (sometimes berry or indehiscent and nut-like). Seed: sometimes winged or hair-tufted.
Genera In Family: 22 genera, +- 657 species: worldwide, especially western North America; many cultivated (Clarkia, Epilobium, Fuchsia, Oenothera). Note: Gaura moved to Oenothera. Fuchsia magellanica Lam. naturalized in northern California.
eFlora Treatment Author: Warren L. Wagner & Peter C. Hoch, family description, key to genera; treatment of genera by Warren L. Wagner, except as noted
Scientific Editor: Robert Patterson, Bruce G. Baldwin.
Genus: LudwigiaView DescriptionDichotomous Key

Common Name: FALSE LOOSESTRIFE, WATER PRIMROSE
Habit: Annual to subshrub or emergent aquatic, often floating, rooting at nodes. Leaf: alternate to opposite. Inflorescence: spike; flowers 1 per bract. Flower: radial; hypanthium 0; sepals 4--5(7), persistent; petals (0)4--5(7), white to yellow; stamens 4 or 10(12), pollen generally shed singly (in California); stigma club-shaped to spheric. Fruit: irregularly dehiscing; wall thick or thin. Seed: free or embedded in woody piece of fruit wall.
Species In Genus: 82 species: +- worldwide. Etymology: (C.G. Ludwig, German botanist, physician, 1709--1773) Note: Many polyploids.
eFlora Treatment Author: Peter C. Hoch & Brenda J. Grewell

Ludwigia hexapetala (Hook. & Arn.) Zardini, H. Gu, & P.H. Raven
NATURALIZED
Habit: Perennial herb, subshrub, emergent aquatic, 3--20(40) dm, matted, with thick white spongy roots at floating nodes, creeping to erect on land, often climbing on other pls. Stem: prostrate to erect, flower shoot erect, simple or branched distally, glabrous (floating) to spreading-hairy (erect). Leaf: alternate, 3--11(15) cm; petiole (0)5--30(56) mm; blade narrowly elliptic to oblanceolate or widely obovate, entire, +- glabrous, tip generally mucronate. Inflorescence: bracts lanceolate to lance-ovate; pedicel (9)13--25(85) mm. Flower: sepals 5(6), 12--19 mm; petals 5(6), 18--29 mm; stamens 10(12) in 2 unequal sets, anthers 1.5--4.5 mm. Fruit: reflexed, falling with pedicel; 14--26 mm, cylindric, tapered to pedicel, +- spreading-hairy. Seed: 1.2--1.5 mm, embedded in woody inner fruit wall. Chromosomes: 2n=80.
Ecology: Lake margins, wetlands; Elevation: < 300 m. Bioregional Distribution: NCo, s NCoRO, GV, CCo, SnFrB, SCo; Distribution Outside California: Oregon, Washington, southeastern United States (native?), Central America, southern South America, Europe. Flowering Time: May--Dec Note: Invasive weed.
Synonyms: Jussiaea uruguayensis Cambess., in part; Ludwigia grandiflora subsp. hexapetala (Hook. & Arn.) G.L. Nesom & Kartesz
eFlora Treatment Author: Peter C. Hoch & Brenda J. Grewell
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Citation for this treatment: Peter C. Hoch & Brenda J. Grewell 2016. Ludwigia hexapetala, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=31665, accessed on May 02, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 02, 2016.


Ludwigia hexapetala
click for enlargement
© 2014 Neal Kramer
Ludwigia hexapetala
click for enlargement
© 2014 Neal Kramer
Ludwigia hexapetala
click for enlargement
© 2014 Neal Kramer
Ludwigia hexapetala
click for enlargement
© 2015 Neal Kramer
Ludwigia hexapetala
click for enlargement
© 2015 Neal Kramer
Ludwigia hexapetala
click for enlargement
© 2014 Neal Kramer

More photos of Ludwigia hexapetala in CalPhotos


Geographic subdivisions for Ludwigia hexapetala:
NCo, s NCoRO, GV, CCo, SnFrB, SCo;
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.