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The function of providing geographic ranges in a botanical resource is to help the user predict where plant taxa can be expected to grow. Formulating such predictions is always a challenge---particularly so in California. The state is large (some of it still poorly explored botanically), has great topographic complexity, and contains an unusual diversity of climates and habitats.Hickman in The Jepson Manual see pp. 37--48
Th lists are derived from the same master list of taxa and distributions as the online distribution maps and the same caveats apply. The distribution hierarchy detailed in The Manual, has been interpreted strictly--perhaps more strictly than was intended by some authors or editors.
For example the recorded distribution of some 230 plants in The Manual is the California Floristic Province (CA-FP) only. Within CA-FP, The Manual delimits 28 subregions. In the hypothetical case of a plant occurring in all of the subregions but the southern Channel Islands, an author or editor might have chosen, in the interests of brevity and generality, to indicate "CA-FP" rather than "CA-FP (exc s ChI)".
Non-occurrence of a plant in an indicated area is difficult to document, but we will especially value your input on those types of possible errors. Here is a form that will facilitate feedback.
As part of the Interchange, these attributed distributions will be verified. Thus the lists at any time will reflect the original distribution presented in The Manual as modified by subsequent investigation.
A map showing Sorensen similarity accompanies each list of the lowest level categories.
Note: some of these lists contain more than a thousand names: the files may be larger than 100K.