Heuchera

In determining flower measurements as given in the key, mature (but not over-mature) flowers should be used; by the time the anthers are shed, the flowers have generally enlarged somewhat.

1. Perianth at anthesis 3–5 (–5.5) mm long, the deepest sinus usually less than half the length of the calyx.

H. americana

1. Perianth at anthesis (5–) 6–9 mm long, the deepest sinus ca. half the length of the calyx.

H. richardsonii

All species found in Heuchera

Heuchera americanaALUM ROOT 
Heuchera richardsoniiPRAIRIE ALUM ROOT 

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 17, 2017. http://www.michiganflora.net/genus.aspx?id=Heuchera.