Many of the vegetation datasets have been cooperatively produced, but will have stewards responsible for the maintenance and updating of the data. Steward organizations for many of the datasets are listed after the dataset in parentheses, and include the California Dept. of Fish and Wildlife (CDFW), the California Native Plant Society (CNPS), the National Park Service (NPS), the Nature Conservancy (TNC). All of the National Park Service vegetation datasets are available through NPS. They can also be found through 
BIOS.
Each map will have map classes at a variety of levels in the NVCS hierarchy from Macrogroup down to Association. More recent maps generally conform to the Survey of California Vegetation Standards (PDF).
Northern California and Sierra Nevada
Central Valley and Bay and Delta
Central Coast and Range
California Deserts
Southern California Coast