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 a hundred stems statewide (as of 17 Oct 2019). The species occurs 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, with some disjunct populations in the Piedmont.

Optimum survey window. Late-summer to fall (Aug to Oct), when fruits are borne.

Where to report? Please carefully review the diagnostic features below. If you think you've found a population of the species, please report it to 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 (the hairs spreading), alternate leaves, four sepals (these are persistent on the fruit), no petals, and sessile, more or less squatty (rather than elongate) capsules. For a technical key to these species, click the "Key" link at the top of the page.

Raven's Seedbox is most similar to Hairy Seedbox (L. pilosa). The two are best distinguished as illustrated below. In Raven's Seedbox, the sepal tips are ascending, whereas in Hairy Seedbox the sepal tips are reflexed. In addition, the bracteoles are attached distinctly at the base of the capsule in Raven's Seedbox, while above the base in Hairy Seedbox. Under the microscope, seed surface distinctions are also evident. Seed surface cells are elongate transverse to the long axis of the seed in Raven's Seedbox, but orbicular in Hairy Seedbox.