|Photo by Wayne Matchett, SpaceCoastWildflowers.com|
|Division:||Magnoliophyta - Flowering plants|
|Class:||Magnoliopsida – Dicotyledons|
|Family:||Fabaceae ⁄ Leguminosae|
|Natural range of Lupinus diffusus from USDA NRCS Plants Database.|
Common names: Blue sandhill lupine.
"Annual, biennial, or perennial herbs, rarely shrubs. Leaves palmately compound with (3) 5-15 (18) leaflets or 1-foliolate and then appearing simple; stipules partly adnate to the petiole, often caduceus. Racemes terminal with pedicellate, papilionaceous flowers subtended by usually caduceus bracts. Calyx conspicuously 2-lipped with the lips entire to deeply lobed; corolla commonly blue, white or yellow, rarely purplish, standard broadly obovate to orbicular and typically with reflexed margins; stamens monadelphous, filaments o two lengths, the longer with globose, versatile anthers, the shorter with linear, basifixed anthers; ovary sessile. Legume oblong, flattened, 2-12 seeded." 
"Cespitose herb perennating, decumbent stems 2-4 dm or more long from a woody taproot; more or less densely short-pubescent throughout. Leaves 1-foliolate, evergreen, mostly oblong to elliptic, 4-12 cm long, 1.5-5 cm wide; petiole 3-10 cm long; stipules fused to petiole for (0.3) 0.8-2 (3) cm , free portion filiform, 0.5-2.5 cm long. Racemes 1-3 dm long; pedicels 1-4 mm long, each subtended by a caduceus, subulate bract 4-8 mm long, the lower 3-lobed with the 2 laterals linear and ca. 2 mm long and the central 5-7 mm long; petals light to deep blue, the standard with a conspicuous cream spot. Legume linear-oblong, 3-4.5 cm long, 7-9 mm broad, appressed-pubescent with trichomes ca. 2 mm long.' 
L. diffusus ranges from southeastern North Carolina to southern Florida, and west to Mississippi.
In the Coastal Plain in Florida, L. diffusus can occur in longleaf pine-scrub oak sand ridges, sand pine scrubs, deciduous scrub oak barrens, sand pine woods, and live oak-palmetto scrubs.
L. diffusus had no response to agricultural-based soil disturbance in South Carolina coastal plains communities.
Associated species include Carya floridana, Lechea, Chamaecyparis, Quercus virginiana, Q. laevis and Q. incant.
Like many other legumes, L. diffusus has root nodules that contain nitrogen fixing bacteria that provide the plant with nitrogen, even in poor soils.
L. diffusus flowers from March through May and fruits from June to July.
Seeds are dispersed by wind and animals.
Responds quickly to soil disturbance and fire.
Herbivory and toxicology
Lupinus diffusus has been observed at the Archbold Biological Station to host bees from the Apidae family such as Bombus griseocollis and leafcutting bees from the Megachilidae family such as Anthidiellum notatum rufomaculatum, A. perplexum and Megachile exilis parexilis. The legumes are toxic to livestock. Foliage is eaten by aphids and caterpillars.
Conservation, cultivation, and restoration
Flowers of Lupinus diffusus
Photo by Wayne Matchett, SpaceCoastWildflowers.com
References and notes
- Weakley, A.S. 2015. Flora of the southern and mid-atlantic states. Working Draft of 21 May 2015. University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
- Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 586-7. Print.
- Brudvig, L.A., J.L. Orrock, E.I. Damschen, C.D. Collins, P.G. Hahn, W.B. Mattingly, J.W. Veldman, and J.L. Walker. (2014). Land-Use History and Contemporary Management Inform an Ecological Reference Model for Longleaf Pine Woodland Understory Plant Communities. PLoS ONE 9(1): e86604.
- Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: October 2015. Collectors: Loran C. Anderson, J. Beckner, D. Burch, George R. Cooley, A.H. Curtiss, H.A. Davis, R.K. Godfrey, M. Hopkins, Ann F. Johnson, Beverly Judd, Walet Judd, Edwin Keppner, R. Kral, O. Lakela, Robert J. Lemaire, Fred L. Lewton, Sidney McDaniel, Grady W. Reinert, Paul O. Schallert, D.B. Ward, Kenneth A. Wilson, Carroll E. Wood, Jean Wooten. States and Counties: Florida: Brevard, Clay, Citrus, Coffee, Hernando, Highlands, Hillsborough, Lake, Levy, Marion, Okaloosa, Osceola, Polk, Santa Rosa, Seminole, Walton, Washington. Compiled by Tall Timbers Research Station and Land Conservancy.
- [] UNF Landscape Accessed: February 9, 2016
- [] Dave's Garden Accessed: February 9, 2016
- [] Accessed: February 9, 2016
- Deyrup, M.A. and N.D. 2015. Database of observations of Hymenoptera visitations to flowers of plants on Archbold Biological Station, Florida, USA.