Tanacetum

1. Leaves undivided (though regularly toothed).

T. balsamita

1. Leaves pinnatifid or bipinnatifid.

2. Rays absent or yellow.

3. Heads (12–) 13–19 (–22) mm broad; leaves ± hairy.

T. bipinnatum

3. Heads 5–10 mm broad; leaves glabrous or nearly so.

T. vulgare

2. Rays present, white or pink.

4. Rays white, 4 – 8 mm long; heads numerous per stem (except in depauperate plants)

T. parthenium

4. Rays bright pink, fading to a dull pale pink, ca. 12 – 20 mm long; heads few (1-3) per stem

T. coccineum

All species found in Tanacetum

Tanacetum balsamitaCOSTMARY, MINT-GERANIUM 
Tanacetum bipinnatumLAKE HURON TANSY 
Tanacetum coccineumPAINTED DAISY, PYRETHRUM DAISY 
Tanacetum partheniumFEVERFEW 
Tanacetum vulgareCOMMON TANSY, GARDEN TANSY 

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. June 22, 2017. http://michiganflora.net/genus.aspx?id=Tanacetum.