A number of excellent online resources exist to support your plant research for a project. Following is an overview of these websites and how to use them.

CNPS Rare Plant Inventory  

  • From the landing page click the “Visit RPI” button to enter the database, the landing page also has a link to a video tutorial, “How to Use the Rare Plant Inventory.”  
  • To conduct a nine-quad search click the advance search button on the CNPS Rare Plant Inventory Database page.  
  • From here click the “Location” tab and scroll down to the quad map of California. On the map, select the quad or quads occupied by the project and select surrounding quads. This will populate a list of quad numbers and names. Make note of these as they will be useful when conducting other searches.  
  • Once the relevant quads are selected, scroll down and click the “View All Plants” button to pull up a list of all California Rare Plant Ranked species that have been documented in the selected quads. Note that this is a positive occurrence database, and the absence of a species does not preclude it from being present. This database will provide occurrence data by quad but not a precise location.  
  • The plant list will include California Rare Plant Rank (CRPR) list 1, 2, 3 and 4 taxa. The EIR may or may not include list 3 and 4 species. List 1 and 2 species meet the criteria to require CEQA analysis, but list 3 and 4 species may or may not meet the criteria of CEQA. If a CRPR 3 or 4 species is locally rare, or the population is at an extreme end of the species range, it should be considered for impacts under CEQA.
  • Compare this list to the list of special-status species with the potential to occur provided in the EIR to see if any species were not considered.  

For more information on using the CNPS Rare Plant Inventory, see the blog series developed by the CNPS Rare Plant Program team.

California Natural Diversity Database (CNDDB)

The CNDDB is a database maintained by the California Department of Fish and Wildlife (CDFW). Performing a nine-quad search in CNDDB will give you a list of CRPR 1 and 2 occurrences submitted to the database, this may also include species that were previously listed as 1 or 2, or species that are or have been listed under the Federal or California Endangered Species Acts. This database also includes location data for each occurrence, and the occurrences can be viewed on a map using the Biogeographic Information and Observation System (BIOS) viewer. This can be very useful to see where special status species have been documented within the project footprint. Many EIRs will use a CNDDB search to develop the list of special status plants with the potential to occur. 

  • To perform a CNDDB search click the Maps & Data link from the list of resources on the CNDDB homepage. 
  • From the Maps & Data page, click the RareFind 5 button to perform a CNDDB query. Note: This will require a CNDDB subscription. 
  • On the RareFind webpage click the “Taxonomic Group” dropdown and select the “Plants” box. Now, click the “Locational Features” dropdown, then the “Quad” dropdown. Enter each quad you are querying into the search box, then use the arrows to move the relevant quads from the search results on the left to the box on the right. Once all relevant quads have been added, click the “Run Query” box at the top of the page. 
  • The “Results” page will have a species list in the top box, and the bottom box will display each occurrence of the species selected from the top box. 
  • To view the locations on a map, click the “BIOS” button at the top of the page, we typically want to select “Show map with all returned occurrences,” but you may select to view a single species as well.  

CNDDB data can also be downloaded as a shapefile for use in ArcGIS.  


The Calflora database includes natural occurrences of both native and non-native species and has many search and filter options. This database uses a wide range of data sources including user-submitted locations, data from the California Consortium of Herbaria (CCH), and iNaturalist locations, among others. Calflora’s “What Grows Here?” search function is an especially useful tool. 

  • From the Calflora homepage, click the “What Grows Here Link” from the menu on the left side of the page. 
  • Click the “Area” dropdown, then click the “Draw a Polygon” dropdown.
  • Now, select “in polygon” and click the “start drawing” button. 
  • Zoom the map to the project area and start dropping points to outline the approximate footprint of the project area. Once the project area is defined, click the search button. 
  • The results will list all species with documented locations within the search area. These can be grouped by lifeform, displayed as a full list, or can be filtered to display certain results. 
  • To filter your results, click the “Plant Filter” dropdown and select the criteria you would like to filter for. For analyzing an EIR you can save time by looking only at rare plants. Select “rare” from the “Status” dropdown, then click the “Search” button again to filter results. 
  • Clicking on the scientific name of each taxon will take you to the “Calflora Taxon Report,” which will display locations and more details on the taxa. 
  • Selecting a county will allow you to view the observation search page, where you can see a record detail for each documented location. Note: Not all location data or identifications will be accurate; checking the record detail may offer more information on the data source and location quality.

Consortium of California Herbaria (CCH)

The (CCH) is another good source of information, as most herbarium vouchers will have location data associated with the collection. The Consortium of California Herbaria is an organization that supports all herbaria in California. It provides information on California vascular plant specimens housed in herbaria worldwide, and information for herbarium specimens housed by all participating CCH members. There are two portals, CCH1 includes data on California plant specimens found in herbaria worldwide, CCH2 includes data from CCH member herbaria. From the CCH2 search page you can select “Map Search”, then enter the taxa you are interested in to see locations where vouchers were collected. Click on the locations for more details on the collection. 


iNaturalist is another useful tool with a crowd-sourced species identification system and organism occurrence recording tool. Using iNaturalist, you can search for occurrences of a specific taxa or view all occurrences within an area in a map or list view. If your account has at least 50 verified occurrences you are allowed to create a “place” from a KML file, this will allow you to view all occurrences within a specified boundary. Many scientists and taxonomic experts contribute to the iNaturalist community by helping to identify observations resulting in “research grade” location data for many occurrences.  Keep in mind, however, that this is open crowd-sourced data and not all location information or identifications will be accurate.