In the official taxonomic ordering of botanical names a family is a collection of tribes and a tribe is a collection of genera. For most of us, the tribe is not important and we like to conveniently assign a genus directly to a family. Families exhibit common characteristics that in a subjective sense group them together. For example, Juglandaceae (the walnut family) consists of 10 genera which bear nuts in a fleshy husk. Other characteristics such as their leaf shape and arrangement distinguish them in the minds of botanists from similar plants. Some families are quite large, such as Asteraceae (the sunflower family), which contains 1677 genera.

Subjective by their very nature, family names have recently become even more confusing with advancements in genetics. Genera are sometimes reassigned to different families and well-known families are renamed or disappear altogether. Making sense of this is the task of hard working researchers. The Compleat Botanica uses the family names of Walters & Keil who follow Cronquist in their general classification. This scheme is modified to show the validly published names above the rank of genus as identified by Reveal. The result is a taxonomic hierarchy of 1652 family names which give useful clues to the origin of the plant and its generic name.