California Plant Families: West of the Sierran Crest and Deserts

Glenn Keator, a knowledgeable advocate for the use of California natives in gardens, has written several books of value on the subject. In his latest, Keator notes that California has about 172 native and naturalized vascular plant families. (There are, of course, many more plant families present within the state, because of the seemingly endless stream of plants imported from other regions of the world.)

Keator focuses on the plant families found within the California Floristic Province, which includes the coastal region from southwestern Oregon to northwestern Baja California, plus California’s Central Valley. He targets fifty families that represent more than eighty-five percent of California’s flora, and another twenty families that help to define the state’s vegetation. He includes several desert families, such as Cactaceae and Crassulaceae, but defers to other references for detailed information on them.

The Introduction provides an overview of the book and timely comments on the ongoing revision of botanical names, due to advances in DNA analysis. The Key to California Plant Families uses a plant’s physical characteristics to identify its family. Once the key points you to the pages for a particular family, you can read about the native and introduced genera and species within that family and, with careful study, identify the plant of current interest.

In the book’s main section, California Plant Family Accounts, Keator discusses each of these seventy plant families to help the gardener understand “pollination, adaptations to habitats, and life cycles.” These discussions include detailed descriptions of each family and its California genera and species, complemented by Margaret J Steunenberg’s botanical illustrations, which show every important plant in superb line drawings, often with close-up details. The illustrations add greatly to the usefulness of the book. The descriptions are concise and specific, getting to the point of identification with little or no subjective appreciation for the plants.

Some families encompass only a few species, while others have so many native and non-native genera that identification of a single specimen will likely be challenging. For example, the section on the Apiaceae (parsley or carrot family) includes twelve native genera and five non-native genera, but illustrations of only four of those genera.

The book’s Glossary is an essential resource for interpreting the vocabulary of plant anatomy; it is illustrated with Steunenberg’s small drawings, which are truly worth a thousand words. A Common Plant-Names Index and a Scientific Plant-Names Index further help the user to arrive at an identification for a plant in hand.

Gardeners with an interest in California native plants will want to include California Plant Families in their libraries. This is a rare resource—a readable reference for identifying our environment’s significant plants and gaining insights into their cultivation.

Tom Karwin, Master Gardener
Santa Cruz, California