References
For Spigelia
Gould, K.R. 1996. A new, disjunct variety of Spigelia gentianoides (Loganiaceae) from Bibb County, Alabama. Sida 17: 417-421. Google Scholar
Gould, K.R. 1997. Systematic studies in Spigelia. Ph.D. dissertation, U. Tex. Austin, Austin, TX. Google Scholar
Gould, K.R., and R.K. Jansen. 1999. Taxonomy and phylogeny of a Gulf coast disjunct group of Spigelia (Loganiaceae sensu lato). Lundellia 2: 1-13. Google Scholar
Henrickson, J. 1996. Notes on Spigelia. Sida 17 (1): 89-103. Google Scholar
Mathews, K.G. 2023. Loganiaceae. In Flora of North America Editorial Committee. 2023c. Flora of North America north of Mexico. Volume 14, Magnoliophyta: Gentianaceae to Hydroleaceae. Oxford Univ. Press, New York, NY. 505 pp. Google Scholar
Rogers, G.K. 1986. The genera of Loganiaceae in the southeastern United States. J. Arnold Arb. 67: 143-185. Google Scholar
Struwe, L., K.L. Gibbons, B.J. Conn, and T.J. Motley. 2018. Loganiaceae. In Kadereit, J., & V. Bittrich. 2018. The families and genera of flowering plants. XV. Flowering plants. Eudicots. Apiales, Gentianales (except Rubiaceae). Springer, Cham. Google Scholar
Weakley, A.S., R.J. LeBlond, B.A. Sorrie, C.T. Witsell, L.D. Estes, K.G. Mathews, A. Ebihara, and K. Gandhi. 2011. New combinations, rank changes, and nomenclatural and taxonomic comments in the vascular flora of the southeastern United States. J. Bot. Res. Inst. Texas 5: 437-455. Google Scholar