This is a very large and diverse genus of plants. It
herbaceous perennials, vines, shrubs
and small trees.
Taxonomists are always at work debating
about which species belong in each genus. That is why it
can only be estimated that there are between 1,500 and
2,000 species in this genus.
At one time in history, people
thought that all of these plants were poisonous. Some of them
are but many like tomatoes and potatoes contribute greatly to
the average diet of many people today.