1 Leaves all unifoliolate

1 Leaves (all, or at least the upper leaves) trifoliolate.

  2 Longest calyx lobes shorter than the calyx tube; stipe of the loment 4-20 mm long, about 3× or more as long as the calyx; mature leaves without stipels at the base of the petiolules of the leaflets; leaves subverticillate at the top of the stem (alternate in D. pauciflorum); stamens monadelphous; lower margin of the loment incised to the upper suture

  2 Longest calyx lobes longer than the calyx tube; stipe of the loment absent or nearly so, included within the calyx; mature leaves retaining stipels at the base of the petiolules of the leaflets; leaves alternate; stamens diadelphous; lower margin of the loment not incised to the upper suture.

    3 Leaflets narrow, the terminal leaflet < 14 mm wide, and also 4-12× as long as wide, typically thick and strongly reticulate; petioles of midstem leaves 1-10 (-15) mm long; [primarily of the Coastal Plain and lower Piedmont (rarely Mountains) in our area]

    3 Leaflets broader, the terminal leaflet > 15 mm wide, or < 4× as long as wide, typically thin and not reticulate; petioles of midstem leaves various, but > 15 mm long if leaflet proportions are narrow; [collectively widespread in our area].

      4 Stems erect or ascending, not vinelike.

        5 Stipules (5-) 7-20 mm long, > 1 mm wide at the base, clasping or truncate at the base, persistent (most or all of the stipules persisting through the year), 4-20 mm long; leaflets 1.5-3× as long as wide

        5 Stipules 2-6 (-9.5) mm long, < 1 mm wide at the base, narrowed or parallel-sided to the base, caducous (most or all of the stipules falling soon after expansion of the leaves); leaflets 1-8 (-10)× as long as wide