1. Loganiaceae R. Brown ex Martius
Strychnos Family
Katherine G. Mathews
Herbs, subshrubs, shrubs, or trees [lianas], taprooted or rhizomatous. Stems sometimes with pseudodichotomous branching; wood often with internal phloem and vestured pits; colleters often present in axils of leaves and calyx; hairs unicellular or uniseriate. Leaves [in rosettes] usually opposite, sometimes whorled or pseudowhorled, simple, entire, penniveined or with ascending, arcuate lateral veins; stipules or interpetiolar lines absent or present, stipules interpetiolar, leafy, membranaceous, or reduced to ridge, or paired at leaf base. Inflorescences terminal or axillary, cymose, dichasial, monochasial, or thyrsoid [solitary flowers]; bracteoles (0–)2(or 3). Flowers bisexual [unisexual]; perianth [4 or]5-merous; sepals valvate or imbricate [contort], equal or unequal [calycophyllous, replaced by involucre]; corolla yellow, white, green, pink, red, or purple, tubular, funnelform, campanulate, or urceolate [rotate], glabrous or hairy outside and within; stamens [1–]5, alternating with corolla lobes; filaments glabrous [hairy], distinct [connivent or coherent]; anthers 2- or 4-celled, glabrous [hairy], dehiscence introrse [latrorse], pollen colporate to colpate; ovary superior or semi-inferior, 2-locular, syncarpous or apically apocarpous, glabrous or hairy, ovules [1–]5–50 per locule, anatropous or hemi-anatropous, placentae axile, frequently peltate; styles [0 or]1, persistent or deciduous, filiform, glabrous or hairy. Fruits capsules or berries [drupes], capsule dehiscence septicidal and usually loculicidal, separating partly or completely into 2 or 4 valves, also circumscissile in Spigelia, berries yellow or orange to green [red, brown, blue-black]. Seeds polyhedral, round, or lens-shaped, not winged [winged], endosperm fleshy or cartilaginous [starchy], embryo straight.
Genera 15, species ca. 400 (3 genera, 11 species in the flora): c, se United States, Mexico, West Indies, Central America, South America, Asia, Africa, Indian Ocean Islands, Australia; pantropical, temperate areas.
A monophyletic Loganiaceae has been delineated to contain 15 genera, including Antonia Pohl, Bonyunia M. R. Schomburgk ex Progel, Gardneria Wallich, Geniostoma J. R. Forster & G. Forster, Labordia Gaudichaud-Beaupré, Logania R. Brown, Mitrasacme Labillardière, Mitreola, Neuburgia Blume, Norrisia Gardner, Phyllangium Dunlop, Schizacme Dunlop, Spigelia, Strychnos, and Usteria Willdenow (C. L. Frasier 2008), as opposed to the broader, polyphyletic concept of A. J. M. Leeuwenberg and P. W. Leenhouts (1980). The North American genera Buddleja (including Emorya) and Polypremum, formerly included in Loganiaceae in the broad sense, are now commonly grouped together in Buddlejaceae (Lamiales); the most recent treatments place Buddleja in Scrophulariaceae (D. C. Albach et al. 2005) and Polypremum into Tetrachondraceae (S. J. Wagstaff 2004). Gelsemium has been excluded from Loganiaceae in the narrow sense and placed in Gelsemiaceae (L. Struwe et al. 1994).
In the past, segregate families have been proposed to segregate various groups from Loganiaceae in the narrow sense, including Spigeliaceae Berchtold & J. Presl and Strychnaceae de Candolle ex Perleb; because knowledge of intergeneric relationships is still provisional, they are not recognized here.
Several genera are known to contain bioactive compounds, including secoiridoids and indole alkaloids, and have been used as drugs, poisons, and medicines, particularly Spigelia and Strychnos.
SELECTED REFERENCES Frasier, C. L. 2008. Evolution and Systematics of the Angiosperm Order Gentianales with an In-depth Focus on Loganiaceae and Its Species-rich and Toxic Genus Strychnos. Ph.D. dissertation. Rutgers, The State University of New Jersey. Leeuwenberg, A. J. M. and P. W. Leenhouts. 1980. Loganiaceae. Taxonomy. In: H. G. A. Engler et al., eds. 1924+. Die natürlichen Pflanzenfamilien…, ed. 2. 26+ vols. Leipzig and Berlin. Vol. 28b(1), pp. 8–96. Mennega, A. M. W. 1980. Loganiaceae. Anatomy of the secondary xylem. In: H. G. A. Engler et al., eds. 1924+. Die natürlichen Pflanzenfamilien..., ed. 2. 26+ vols. Leipzig and Berlin. Vol. 28b(1), pp. 112–161. Rogers, G. K. 1986. The genera of Loganiaceae in the southeastern United States. J. Arnold Arbor. 67: 143–185.
