It is often not easy to identify our gaillardias, all of which are escapes from cultivation. The chief character usually given is the annual habit of G. pulchella, but as that species is often quite “woody” at the base, determining its duration is difficult. Of other characters given in the literature, only achene length appears to discriminate consistently. Color patterns can be less reliable than stated in the key.
1. Plants perennial; rays yellow at least on the apical half; body of achenes ca. (3.5–) 4–5 (–6) mm long.
1. Plants annual; rays deep red-purple more than half (basal half) their length; body of achenes ca. 2–2.5 mm long.
All species found in Gaillardia
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. October 18, 2017. http://michiganflora.net/genus.aspx?id=Gaillardia.