<i><a href="//commons.wikimedia.org/wiki/Aspidotis_densa" title="Aspidotis densa">Aspidotis densa</a></i> from Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. Vol. 1: 33. Courtesy of Kentucky Native Plant Society.
Britton, N.L., and A. Brown
1913
<a rel="nofollow" class="external free" href="https://plants.usda.gov/java/largeImage?imageID=pede13_001_avd.tif">http://plants.usda.gov/java/largeImage?imageID=pede13_001_avd.tif</a>