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Floristic Atlas of the San Juan Islands, Washington

The Floristic Atlas of the San Juan Islands provides an easy to use tool for mapping the distributions of vascular plant species within the San Juan Islands, and for analyzing and comparing species distributions and biogeographical patterns.

The atlas is based on over 6,700 voucher specimens from the San Juan Islands that are housed at the UW Herbarium as well as observational records from recent surveys of the islands. Included within the atlas dataset are nearly 4,000 specimens from many of the smaller islands collected during comprehensive botanical surveys of the San Juan Islands by the UW Herbarium's David Giblin and The Nature Conservancy's Peter Dunwiddie between 2004 and 2009. Learn more about the San Juans Islands Surveys.


» Go to the Atlas




Map comparing the distributions of Sanicula crassicaulis var. crassicaulis (green dots) and Sanicula crassicaulis var. tripartita (red dots) in the San Juan Islands. S. crassicaulis var. crassicaulis is more widespread. Neither variety has yet been documented from the northeastern portion of the islands.





Location of the San Juan Islands in northwestern Washington.

Location of the San Juan Islands

The San Juan Islands are positioned between the southern end of the Straight of Georgia and the northern end of Puget Sound, in northwestern Washington about 70 miles northwest of Seattle. This archipelago consists of four large islands accessible by ferry and numerous small islands and islets. The Islands lie within the rain shadow of the Olympic Mountains to the southwest. This rainshadow effect, when combined with exposed rocky headlands and gravelly soils on many of the islands, creates a climate suitable for cacti and other species not normally found in western Washington.

About the Atlas

The San Juan Islands Atlas provides a flexible mapping interface that allows you to do more than simply place dots on a static map. Features available through the atlas include:

  • Browse through a list of all taxa currently documented from the San Juan Islands region. Clicking on a taxon name in the list will show its distribution on the map, either alone, or along-side other taxa.
  • Perform custom searches to display groups of specimens according to criteria other than taxon name. Examples include: displaying all collections and sites for a single collector, searching for all taxa collected from a specific island, and displaying specimens based on their year of collection.
  • Zoom into the map far enough to see more precisely the locations of each specimen.
  • Change the map type to see how species' distributions correlate with different geographical and environmental features. Map types include satellite views, street maps, topography, vegetation, and climate.
  • Overlay other information on the map, such as place names, political boundaries, a TRS or latitude/longitude grid, or the locations of all collection and survey sites.
  • Display the distributions of multiple taxa on the same map using differently colored symbols, allowing easy comparisons of the distributions of each taxon. Likewise, the results of multiple custom searches can be displayed on the same map.
  • Download specimen data for the displayed taxa in several formats, including tab-delimited text and Google Earth's KML format.

    » Go to the Atlas




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