Shrubs or small trees . Wood white to yellowish, soft, brittle, even-grained; secretory canals in outer pith; resin yellowish. Leaves alternate, not aromatic; stipules absent; petiole and veins with secretory canals. Inflorescences axillary catkins, erect or lax. Flowers unisexual, staminate and pistillate on different (rarely on same) plants, inconspicuous, sessile; perianth absent or of small, undifferentiated sepals, hypogynous; pistils simple (rarely compound), 1(-2)-carpellate; ovary superior; placentation parietal; ovule 1, pendulous; style 1. Fruits drupes, leathery, dry.

Leitneriaceae are a relict family confined to the flora area and occurring on coastal and riverine flood plains of the Atlantic and Gulf coasts. The fossil record of the family extends to the Middle Oligocene (32-30 M.Y.B.P.).

Taxonomic affinities are uncertain. Various alliances have been suggested: Hamamelidales (A. Cronquist 1981), Sapindales (R. M. T. Dahlgren 1980), and Rutales (R. F. Thorne 1983) of the Rutiflorae. Biochemical studies (D. E. Giannasi 1986; F. P. Petersen and D. E. Fairbrothers 1983, 1985) suggest affinities with Simaroubaceae in Rutales.

SELECTED REFERENCES

Abbe, E. C. and T. T. Earle. 1940. Inflorescence, floral anatomy and morphology of Leitneria floridana. Bull. Torrey Bot. Club 67: 173-193. Channell, R. B. and C. E. Wood Jr. 1962. The Leitneriaceae in the southeastern United States. J. Arnold Arbor. 43: 435-438. Giannasi, D. E. 1986. Phytochemical aspects of phylogeny in Hamamelidae. Ann. Missouri Bot. Gard. 73: 417-437. Jarvis, C. E. 1989. A review of the order Leitneriales Engler. In: P. R. Crane and S. Blackmore, eds. 1989. Evolution, Systematics, and Fossil History of the Hamamelidae. 2 vols. Oxford. Vol. 2, pp. 189-192. [Syst. Assoc. Special Vol. 40B.] Petersen, F. P. and D. E. Fairbrothers. 1983. A serotaxonomic appraisal of Amphipterygium and Leitneria--two amentiferous taxa of Rutiflorae (Rosidae). Syst. Bot. 8: 134-148.