The California Native Plant Society actively supports and contributes to the creation and publication of local floras. These guides provide regional lists of plants, often covering a county jurisdiction. Since floras detail the local distribution of plants within a specific area, they are foundational tools for field, consulting, and conservation botanists. They’re also needed to determine which taxa within an area are rare to that area. (Learn more about CNPS locally rare plant initiatives.)
What exactly is floristics?
Floristics — the study of local flora — is defined as “a branch of phytogeography that deals with plants and plant groups from the numerical standpoint.” Floristics covers how many taxa, categories of taxa, groups, etc., that are in a given area. Statistical analysis can be applied to the flora of any given area, which is often then used to compare the flora of one area against another. Floristics also deals with taxa that are common, widespread, restricted, and/or rare.
The study of floristics can also be used to compare different environmental variables, such as substrate differences, temperature ranges, slope and aspect, to name just a few. Several mathematical models can be used to analyze this type of data.
The most basic component of any floristic study is knowing what plants are present.
For valid, meaningful results, the flora of the study area must be known. Developing a flora is the most fun, and tedious, work of a botanist. It is fun because it usually involves exploring the study area and collecting and documenting what species are found. It is tedious because a tremendous amount of work must be done to compile and maintain occurrence records, analyze data, figure out what plant are found, all of which takes a great deal of time and effort. The reward is the result — a tool that every botanist visiting the area will likely use.
Local and regional flora
With 58 counties, a Mediterranean climate (for most of the state), a latitude range of almost 10 degrees, an elevation range from well below sea level to over 14,000 feet, and tremendously varied topography and geology, California’s flora is extremely rich and diverse. Statewide floras (Munz’s A Flora of California and more recently The Jepson Manual, Higher Plants of California) provide the basics, listing all the native and naturalized vascular plant taxa known to occur in the state at the time of their publications; however, they cannot possibly include locational data that a local or regional flora can.
A recent survey of local floras of areas within California found that floras exist for only 22 of the 58 California counties, and of those some are just checklists (based on voucher specimens). This means that much floristic work is needed to have a true and complete understanding of California’s flora. In addition, we have the opportunity to create other types of floras written and published for sub-county areas, such as a mountain or valley, or park.
Below is a list of the published floras listed by county. It also indicates which counties lack any published floristic studies.