The Solanaceae are a medium-sized family of flowering plants belonging to the Asterids (in the sense of the Angiosperm Phylogeny Group (APG) treatment of the major groups of flowering plants, see APG, 2003).
Botanists today recognise and give names to clades, or monophyletic groups, containing all the descendents of a common ancestor, rather than to groups of similar looking plants. This has meant that some traditional groupings are no longer recognised, and that some surprising evolutionary relationships have been revealed. Asterids, including the Solanaceae, however, are one group that has stood the test of time.
The Asterids share one very obvious feature – a tubular corolla, where the petals are fused to some degree. This character has long been considered important by taxonomists, and this large group used to be called the “Sympetalae” (from the Latin sym – joined; petalae – petaled). The relationships of these groups are the subject of active research and DNA sequence data has been very important in working out patterns of evolutionary relatedness in the flowering plants.
Asterids are one of the major clades of flowering plants, and contain many plants of economic importance to humans. The ten orders of Asterids are:
- Cornales (dogwoods, hydrangeas and their relatives)
- Ericales (blueberries, Brazil nuts, tea, ebony and their relatives)
- Garryales (silktassels, aucubas and relatives)
- Gentianales (gentians, coffee and relatives)
- Solanales (morning glories, sweet potatoes, potatoes, tomatoes and relatives)
- Lamiales (mints, African violets, sesame and relatives)
- Aquifoliales (hollies, yerba mate and relatives)
- Apiales (carrots, coriander, ivy and relatives)
- Dipsacales (teasels, vibrunums, honeysuckles and relatives)
- Asterales (daisies, sunflowers and relatives)
Each of these orders contains several to many families (see the Angiosperm Phylogeny web site) - the family Solanaceae belongs to the order Solanales and is most closely related to the family Convolvulaceae (morning glories and relatives). The Solanaceae contains between 3000 and 4000 species in some 90 genera, the largest of which is Solanum, with 1500-2000 species, almost half the diversity of the family.
The Angiosperm Phylogeny Group (2003) An update of the Angiosperm Phylogeny Group classification for the order and families of flowering plants: APG II. Botanical Journal of the Linnean Society, 141: 399-436. 2003.