Included in Caprifoliaceae in Michigan Flora.
1. Plant an erect shrub; leaf blades acute to acuminate, toothed (even if minutely) below as well as beyond the middle; flowers spreading, usually more than 2 in an inflorescence, on peduncles shorter than the subtending leaves; ovary and fruit with bristles not gland-tipped.
1. Plant with long-trailing stem from which arise short erect nearly herbaceous leafy shoots; leaf blades obtuse or rounded, shallowly toothed on apical half only; flowers pendent, normally in pairs on long peduncles terminating the leafy shoots and much exceeding the leaves; ovary and fruit with gland-tipped bristles.
All species found in Linnaeaceae
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. October 20, 2019. https://michiganflora.net/family.aspx?id=Linnaeaceae.