Natural distribution map for <i>Ceanothus thyrsiflorus</i>
Elbert L. Little, Jr., of the U.S. Department of Agriculture, Forest Service, and others
1976
<a rel="nofollow" class="external text" href="https://catalog.data.gov/dataset/digital-representation-of-atlas-of-united-states-trees-by-elbert-l-little-jr">USGS Geosciences and Environmental Change Science Center: Digital Representations of Tree Species Range Maps from "Atlas of United States Trees" by Elbert L. Little, Jr. (and other publications)</a>