Circaea

1. Flowers on glabrous, erect to ascending pedicels, open before elongation of the axis of the raceme (hence the open flowers appearing clustered at end of raceme); anthers ca. 0.2–0.3 mm long; fruit 0.9–1.2 mm thick (excluding hairs), not ridged and grooved.

C. alpina

1. Flowers on pubescent, widely spreading pedicels, open after elongation of the axis of the raceme; anthers 0.6–0.9 mm long; fruit 2–2.8 mm thick, when fully mature with several strong ridges and grooves.

C. canadensis

All species found in Circaea

Circaea alpinaSMALL ENCHANTER'S-NIGHTSHADE 
Circaea canadensisENCHANTER'S-NIGHTSHADE 

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. June 25, 2017. http://michiganflora.net/genus.aspx?id=Circaea.