2. Lobelia L. (lobelia)

Plants annual or perennial herbs (woody elsewhere) usually with milky juice. Leaves sessile to shortly petiolate, lanceolate to oblanceolate or ovate, the margins finely to coarsely toothed. Inflorescences terminal spikes, racemes or panicles, the flowers from the axils of mostly reduced (shorter and narrower than the leaves) bracts. Flowers more or less epigynous, resupinate (inverted by twisting of the stalk), not cleistogamous. Calyces all 5-lobed, more or less actinomorphic, the tube usually ribbed, the lobes usually longer than the tube, sometimes with short, reflexed appendages (auricles) toward the base alternating with the lobes. Corollas zygomorphic, strongly 2-lipped with spreading lobes, the apparent lower lip 3-lobed, the upper lip 2-lobed and split nearly to the base through which the stamens and style are exserted, the tube sometimes with slitlike openings (fenestrate), red, or blue to white (rarely purple). Stamens 5, free from the corolla, the filaments free at the very base but mostly fused into a tube, the anthers also united into a ring around the style, the lower 2 anthers usually shorter than the others and with white tufts of hair. Pistil with 2 carpels. Ovary half to totally inferior, with 2 locules. Style elongating through the filament tube, stigma lobes 2, protruding and expanding through the anther tube after the pollen has been shed. Fruits hemispherical capsules, usually longitudinally ribbed, crowned by the persistent calyx lobes, withered corolla, stamen tube, and style, longitudinally dehiscent by 2 apical pores. Seeds oblong to oblong-elliptic, the surface yellowish brown, with minute wrinkles or tubercles. About 365 species, nearly worldwide, most diverse in tropical and warm temperate regions.

The pyridine alkaloid lobeline is extracted from several species of Lobelia. This alkaloid is similar to nicotine and has been used as an ingredient in antismoking medications (Rosatti, 1986). Lobelia extracts have been used medicinally to treat asthma and bronchitis, but in large doses they can cause nausea, paralysis, and even death (Steyermark, 1963).