Wanted alive! Ludwigia ravenii

Background. Raven's Seedbox (Ludwigia ravenii, Onagraceae) is one of the rarest plant species in North Carolina, currently known from less than thirty populations rangewide (as of Mar 2025). The species has been documented historically from Virginia to Florida, but is rare throughout its range. It is currently considered critically imperiled by NatureServe.

Habitat. Similar to most species of seedbox in the southeastern United States, Raven's Seedbox occurs in wet places, such as ditches, swamps, marshes, and wet savannas. It is primarily known from the Coastal Plain.

Optimum survey window. Summer to fall (Jul to Oct), when flowers and fruits are borne.

Where to report? Please carefully review the diagnostic features below and in the key (linked above). If you think you've found a population of the species, please report it to us and the North Carolina Natural Heritage Program. Careful documentation of the diagnostic features with photographs would be very helpful.

Identification. There are numerous native species of seedbox in North Carolina. Raven's Seedbox belongs to the group of species exhibiting hairy stems, alternate leaves, four sepals (these are persistent on the fruit), no petals, and sessile capsules. For a technical key to these species, click the "Key" link at the top of the page.

Critical to accurate identification of species in the target group are the following characters: stem pubescence (spreading vs. strigillose), sepal color (green vs. white), and seed surface cell shape (elongate vs. essentially isodiametric).

Similar species. Raven's Seedbox is most easily confused with naturally occurring hybrids of other species that also exhibit green sepals and spreading pubescence of stems and capsules. These include L. simulata (L. pilosa x L. lanceolata) and L. pilosa x L. sphaerocarpa. For a diagnostic key and photographs to these (and others), please click the key link above.

Raven's Seedbox has been confused historically also with Hairy Seedbox (L. pilosa). In flower, the two are unmistakeable. Hairy Seedbox exhibits white sepals, sometimes tinged with pink, whereas Raven's Seedbox exhibits green sepals. In fruit, the two are a bit more challenging to distinguish. Note that in Raven's Seedbox, the persistent sepal tips are ascending, whereas in Hairy Seedbox the sepal tips are reflexed. Although sepals of both species often turn reddish in fruit, looking at the base of the adaxial sepal surface can be useful. Generally, one can still detect white in this region for Hairy Seedbox and green for Raven's Seedbox. Under the microscope, seed surface distinctions are clear. Seed surface cells are elongate transverse to the long axis of the seed in Raven's Seedbox, but essentially isodiametric in Hairy Seedbox.