Lupinus floridanus, the Florida lupine, is a species of flowering plant in the family Fabaceae. It is endemic to Florida in the southeastern United States, where it occurs in xeric sandy habitats.
Lupinus floridanus is an annual herb belonging to the unifoliolate lupine species complex of the southeastern United States.
Plants are erect, often somewhat woody at the base, and produce simple (unifoliolate) leaves that are elliptic and moderately pubescent, with the green surface remaining visible through the hairs. Leaves are proportionally elongate, typically 2.4âÂÂ2.9 times longer than wide.
The inflorescences are terminal racemes bearing pink to purple pea-like flowers. The banner petal typically exhibits a pale or cream-colored central eyespot, a diagnostic feature within the complex.
The species was formally described in 2024 by Edward L. Bridges and Steven L. Orzell as part of a comprehensive revision of the unifoliolate Lupinus of Florida.
This revision demonstrated that populations historically treated within Lupinus diffusus represent multiple distinct evolutionary lineages, leading to the recognition of Lupinus floridanus as a separate species.
Lupinus floridanus is part of a clade of unifoliolate lupines endemic to Florida, characterized by adaptations to xeric, fire-maintained ecosystems.
Lupinus floridanus is restricted to peninsular Florida, where it occurs in scrub and inland xeric ridge systems, including the Bombing Range Ridge, extending north to Lake County.
It inhabits well-drained sandy soils in open habitats maintained by periodic disturbance, particularly fire.
Like other members of the unifoliolate Lupinus group, Lupinus floridanus is adapted to disturbance-dependent ecosystems and is associated with fire-maintained habitats.
As a legume, it forms symbiotic relationships with nitrogen-fixing bacteria, allowing it to thrive in nutrient-poor sandy soils.
Lupinus floridanus is a member of the unifoliolate Lupinus species complex of peninsular Florida, a group of closely related taxa segregated from the historically broad concept of Lupinus diffusus based on morphological and geographic differentiation.
Within this complex, species are distinguished primarily by leaf pubescence (density and whether the green surface is visible), leaf proportions, floral characters (especially the banner eyespot), habit, and geographic distribution.
Lupinus floridanus is characterized by moderately pubescent leaves that retain a clearly visible green surface, elongate leaf blades typically 2.4âÂÂ2.9 times longer than wide, and a pale to cream-colored banner eyespot.
It differs from related species as follows:
These distinctions reflect a radiation of closely related taxa adapted to xeric, fire-maintained sandy habitats of peninsular Florida, with Lupinus floridanus representing one of several narrowly endemic lineages within this complex.