| Author | Small | |
| Distribution | Only in the southern Coastal Plain, north for certain to Robeson and Pender counties. A collection record for Dare County, well to the north, may be correct, but another for Cumberland County was collected from a nursery.
A rather restricted range, mostly in the lower halves of the South Atlantic and Gulf Coastal Plains. Ranges north to southern NC, and south to the FL Panhandle and to eastern LA.
| |
| Abundance | Rare; easily confused with, or overlooked as, G. sempervirens. This is a State Special Concern species. | |
| Habitat | This species is limited to blackwater wetlands, mostly growing in shallow water or in damp places. It is typically found along or close to banks of blackwater rivers and creeks, such as the Black, Northeast Cape Fear, Waccamaw, and Lumber rivers. | |
| Phenology | Blooms from mid-April to early May, and fruits from September to October. The species blooms a few weeks later than the very similar G. sempervirens at the same location. | |
| Identification | This is an evergreen, woody vine, with a slender and twining stem, reaching 10 feet or more long. It has opposite and lanceolate to somewhat ovate leaflets, similar to or somewhat broader than those of the very familiar Carolina Jessamine (G. sempervirens). On a given plant, the leaves can vary quite a bit in shape and width, whereas the leaves of Carolina Jessamine are very similar to each other and are narrowly lanceolate. The primary features separating the two are that G. rankinii has narrowly pointed to acuminate sepals, as opposed to somewhat broader (ovate) and more rounded tips to the sepals; and this species has narrower capsules with a longer and more slender beak (tip). Its flowers are mostly non-fragrant, as opposed to somewhat fragrant in Carolina Jessamine. Swamp Jessamine blooms a bit later and the flowers average a bit richer and deeper golden yellow as opposed to medium yellow of Carolina Jessamine. Be careful when attempting to identify this plant, as it is greatly outnumbered by Carolina Jessamine; however, it is certain that there are some undiscovered populations of this easily overlooked species in NC. | |
| Taxonomic Comments | None
| |
| Other Common Name(s) | Rankin’s Trumpet-flower, Rankin’s Jessamine | |
| State Rank | S1S2 | |
| Global Rank | G5 | |
| State Status | SC-V | |
| US Status | | |
| USACE-agcp | FACW link |
| USACE-emp | FAC link |
