Flowering plants, Angiosperms (Magnoliophyta), technically speaking, are divided into two groups, based on the number of seed leaves.  Those with paired seed leaves are Dicotyledonous (Magnoliopsida) plants, or dicots for short.  Monocotyledonous (Liliopsida) plants have but one seed leaf. Grasses, orchids and sedges are monocots. This article, though lengthy, is but a very short introduction to the taxonomy of dicots and monocots. The basic hierarchy of nomenclature begins with Form, and progresses to Variety, Subspecies, Species, Subgenus, Genus, Subfamily, Family and Order. In the interest of brevity, only Order, Family and Genus will be considered here. 

There are practical horticultural benefits of knowing familial and ordinal relationships. For example, if Fireblight has killed photinias in your landscape, you should avoid other members of the Family Rosaceae, since all can be affected. If you appreciate the nitrogen-fixing ability of the Legumes in your vegetable garden and want others for your landscape, select from the listing of genera of the Fabaceae, the Legume Family. Aesthetically, if a certain flower form appeals to you, include more members of the same family in your plantings. The Aristolochiaceae, Asclepiadaceae, Passifloraceae and Rutaceae families include caterpillar food sources for some of the most attractive butterflies. Include hardy members of their genera if you want a "butterfly factory" surrounding your house. And finally, you might want to "keep it in the family" and grow an entire bed or border with plants from just one Family.

The second part of each page includes Families and some of their Genera.  It is not a provincial listing just of plants which we can grow in central Texas, but also includes sources of food, fiber and medicine as well as many other interesting plants.