This family consists of about 16 genera and over 100 species of herbaceous perennials and annuals, trees and shrubs. Most of them are native to tropical and subtropical areas of North America and Africa. However, some of them are adapted to temperate zones.

Note on Taxonomy - Plant taxonomy is the art and science of classifying plants into groupings in order to help people make sense of the huge diversity found in the world. The people who do this for a living are called taxonomists. They are continually evaluating and re-evaluating how plants are classified. For example, with the recent emergence of DNA analysis, many plants have been changing classification.

Also, there is no one, single universal classification system for plants. Rather, there is a lot of debate among taxonomists which may lead to confusion for the average gardener. That is why, in these family listings, you often see the words "about" or "around" when counting the number of genera or species to include. It is also why new families are created and some of the old ones suddenly fade away. So, don't be surprised if you find slightly different information at other sites or sources. Oh, well.