Senna marilandica, “Senna”
Fabaceae
Glabrous leaves, upright habit, leaflets are on the largish side. Useful as a laxative due to the antraquinone content. Popular species for pollinator gardens, forms colonies and bares spectacular yellow flowers. I think that first pic was actually taken at Hot Springs National Park, the second is just below the East Wind glade on the path in.
Erect perennial to 1-2 m, glabrous or sparsely villous.
Leaves glabrous, pinnately compound; leaflets are large (2-5 cm long, 10-25 mm wide), oblong to elliptic. No terminal
leaflet. Stipules lance-linear, deciduous.
Rocky woodlands, alluvial thickets.
Compare with Astragalus canadensis (undersurface of leaf hasstiff straight appressed hairs) and Lathyrus venosus (tendrils).
(Hybrid MOFEP/National Park Fire Ecology Manual)
Paradise Ecological Services 