Dillenius' tick-trefoil, Desmodium glabellum

Here's Dillenius' tick-trefoil, with trepidation. The name Desmodium glabellum was first published by de Candolle in 1825.
By 1887, Asa Gray was calling it D. dillenii (hence the common name?). Then in 1913, Britton and Brown have it as Meiboma glabellum. Fernald in 1950 takes it back to D. glabellum, and Gleason and Cronquist agree in 1963. But then in 1980, Voss lumps the complex together as D. paniculatum. Which brings us to Voss and Reznicek in 2012, who with "some trepidation" return it to D. glabellum. Good for them! It seems to best describe the plants, and it gives me a rationalization for posting three images of plants in the group instead of one! Dillenuis' grows in AL, AR, CT(S), DE, FL, GA, IA, IL, IN, KS, KY, LA, MD, MI, MO, MS, NC, NJ, NY, OK, PA, SC, TN, VA, and WV. It may be that it is not listed for Ontario because no publications for there split the complex. Lenawee Co MI, 7/31/15. Bean family, Fabaceae.