LOGANIACEAE (logania family)

Plants annual or perennial herbs (more commonly shrubs and trees elsewhere). Stems branched or unbranched, often angled or ridged, at least toward the base. Leaves opposite, sessile or nearly so, the bases of each pair connected by a small fused stipular membrane. Leaf blades simple. Inflorescences terminal or sometimes appearing axillary, dichotomously few-branched or unbranched, the main axis or branches consisting of 1-sided spikelike racemes, the axes straight or coiled (scorpioid) at the tip, sometimes short and the flowers then appearing clustered, with small linear bracts. Flowers actinomorphic, hypogynous, perfect, sometimes subtended by a minute linear bract. Calyces deeply 5-lobed or sometimes appearing as free sepals, glabrous, persistent at fruiting. Corollas 5-lobed. Stamens 5, alternating with the corolla lobes, the filaments attached in the corolla tube, the anthers not or barely exserted, attached at their midpoints, yellow. Pistil 1 per flower, of 2 fused carpels. Ovary superior, 2-locular, with usually numerous ovules, the placentation more or less axile. Style 1, the small stigma capitate, sometimes persistent at fruiting. Fruits capsules, obovate in outline, slightly or moderately flattened, deeply notched or 2-lobed (2-horned) at the tip, glabrous, smooth or less commonly with sparse minute papillae. Seeds mostly numerous, occasionally (in Spigelia) as few as 8. About 13 genera, about 350–380 species, nearly worldwide, most diverse in tropical and subtropical regions.

The Loganiaceae have been a controversial family in terms of genera contained and familial limits. The estimate of genera and species above is at the conservative end, but a more liberal interpretation might include up to 29 genera and 575 species (Leeuwenberg and Leenhouts, 1980). Most of the problem is not in the delimitation of genera, but in how many of the genera should be transferred to other families (Backlund et al., 2000). For example, Steyermark (1963) included the genus Polypremum in the Loganiaceae, but it is here treated in the Scrophulariaceae. See the treatment of that family for further discussion. Also, Gelsemium Juss., a small genus of shrubs and woody climbers with usually large yellow corollas, is often included in the Loganiaceae, although recent molecular phylogenetic studies (Oxelman et al., 1999; Backlund et al., 2000) suggest that it is better segregated as its own family, Gelsemiaceae. Of the three species of Gelsemium, which are collectively known as yellow jessamine, the southeastern native G. sempervirens (L.) J. St.-Hil. (Carolina jessamine) is the one most commonly cultivated as an ornamental. Uphof (1922) reported finding the species on mesic slopes near creeks in Butler and Ripley Counties. As no herbarium vouchers have been located to allow verification of any of Uphof’s observations during his ecological and vegetational research in Missouri, G. sempervirens presently is not accepted as part of the Missouri flora. It is a liana with short-petiolate, lanceolate leaves; short, dense spicate clusters of flowers that open one or two at a time and have yellow trumpet-shaped corollas 2–3 cm long; and flattened, oblong capsules.