RANUNCULACEAE (buttercup family) Contributed by Alan Whittemore

Plants annual or perennial herbs, occasionally subshrubs or lianas, sometimes monoecious, dioecious, or with a mixture of perfect and imperfect flowers. Leaves alternate, opposite, whorled, or basal, simple or compound. Stipules absent, but the petioles sometimes expanded or with small appendages. Flowers actinomorphic or zygomorphic, perfect or sometimes imperfect, hypogynous, occasionally with 3 bractlets subtending the calyx. Calyces of 3–6(–20) free sepals, sometimes shed as the flowers open. Corollas absent or of 3 to numerous, free petals, these showy or inconspicuous. Stamens 5 to numerous, free and distinct, the anthers attached at their bases, dehiscing by longitudinal slits. Pistils 1 to numerous per flower, each of 1 carpel (except in Nigella). Ovary superior, 1-locular, the placentation marginal, apical or basal, the ovules 1 to numerous. Style absent or 1, short or long, the stigma 1, often lateral. Fruits berries, follicles, capsules, or achenes, often aggregated on the dome-shaped or elongate receptacle, the seeds 1 to many per fruit. Fifty-six to 60 genera, 2,100–2,500 species, worldwide.

Many species of Ranunculaceae are poisonous due to the presence of benzylisoquiniline alkaloids, and some are a significant danger to livestock.

Nigella damascena L. (love in a mist), an annual species sometimes grown as an ornamental, occasionally escapes in the eastern United States. It was mapped for Missouri by Ford (1997), but the specimen upon which this report was based was a weed in a garden. The species is not yet known to escape into uncultivated ground in Missouri, but it should be watched for. It has several alternate stem leaves and a whorl of leaflike involucral bracts that are 3 times pinnately dissected into narrowly linear segments; large, solitary flowers with showy blue, white, or pink sepals; and a single compound ovary with axile placentation and 5 or 6(–10) linear styles.