Line drawing of <i><a href="//commons.wikimedia.org/wiki/Commelina_erecta" title="Commelina erecta">Commelina erecta</a></i> from Britton and Brown's 1913 <i>An illustrated flora of the northern United States, Canada and the British Possessions</i>
Britton, N.L., and A. Brown
1913
Britton, N.L., and A. Brown.  <i>An illustrated flora of the northern United States, Canada and the British Possessions</i>. Vol. 1: 459.