[3] Genetic data suggest that Nyssa sylvatica and N. biflora are separate species, and Zhou et al. (2018) further propose that the northwest Florida coastal endemic N. ursina is a subspecies of N.

Its range extends north up the Mississippi Valley to southern Arkansas and west and south Tennessee.

[3] The swamp tupelo has minute greenish-white flowers that appear in the spring with the leaves, usually in late April.

After germination, seedlings must grow rapidly to keep the apex and leaves above water, because prolonged submergence during active growth will kill them.

[3] Swamp tupelo normally develops a taproot and has a swollen base to the mean height of the growing season water level.

These specialized roots tolerate high carbon dioxide concentrations, oxidize the rhizosphere, and carry on anaerobic respiration.

[3] Trees and shrubs commonly associated with swamp tupelo are red maple (Acer rubrum), buttonbush (Cephalanthus occidentalis), buckwheat-tree (Cliftonia monophylla), dogwood (Cornus spp.

), swamp cyrilla (Cyrilla racemiflora), swamp-privet (Forestiera acuminata), Carolina ash (Fraxinus caroliniana), loblolly-bay (Gordonia lasianthus), dahoon (Ilex cassine), inkberry (I. glabra), yaupon (I. vomitoria), fetterbush lyonia (Lyonia lucida), and bayberry (Myrica spp.).