The keyword index includes the words in the captions of the pictures which were written by the photographers. The captions frequently include common and scientific names, names of towns and counties, geographical names, and descriptions of vegetation types or of the landscape. For example, areas affected by fire can be located by searching on fire as a keyword. We recommend keyword searches as a way of discovering what is available on this site.
For more comprehensive searches, we recommend searching by geographic quad using quad name or number (note that the quad map is no longer interactive, and the links on this page go to a defunct website), or by genus or species (see below).
The botanical nomenclature used here is that of the period when the photos were taken, which was in the 1920s and 1930s. For example, if you are searching for Douglas Fir you must search for "Pseudotsuga taxifolia" instead of "Pseudotsuga menziesii." A keyword search using a common name should retrieve some (not all) photos featuring that species. Click on the scientific name under 'Subject (Topic)' to retrieve all pictures indexed with that species. The best source for botanical nomenclature of the period is the original edition of W. L. Jepson's Manual of the flowering plants of California. You'll also find the list of species beginning on page 116 of the Field Manual.
Once you have found the names for quads and species, you can use the search page for combined searches that will find those records where both names appear.