A large family of dicotyledonous plants commonly called the potato or nightshade family. It contains about 90 genera and some 3000 species have been described. However the actual number of species may be closer to 2000 since the great infraspecific variation seen in many species has led to taxonomic confusion and some species being given a variety of different names. The Solanaceae are cosmopolitan in distribution though there are concentrations of genera in Central and South America and Australia. The majority of solanaceous plants are herbaceous. The leaves are exstipulate and the flowers are usually regular and borne in a cyme. Most commonly there are five sepals and petals, more or less fused, and five anthers. In the largest genus, Solarium (about 1500 species), the flowers characteristically possess a column of touching, but not fused, stamens, which are particularly prominent because of the downward-turned petals. The fruit is usually a berry, though sometimes a capsule, as in henbane (Hyoscyamus ni-ger) and thorn apple (Datura stramonium).
Many solanaceous plants are poisonous due to their possession of alkaloids, e.g. atropine found in deadly nightshade (Atropa belladonna) and nicotine found in tobacco (Nicotiana tabacum). Others are important as food plants, especially the potato (Solanum tuberosum) and tomato (Lycopersicon esculentum). The aubergines and the various capsicums also belong to this family. The genus Nicotiana includes the important cash crop tobacco and various ornamental species. Other ornamentals include species of Petunia, Schizanthus (butterfly flowers), and Salpiglosis (velvet flowers).