Life … Plants Vascular Plants Dicots Gentians, Dogbanes, Madders, and Allies Dogbanes and Milkweeds Metastelma Smallflower Swallow-wort species 20 observations Smallflower Swallow-wort Metastelma parviflorum Key traits Layer Vines Plant type Perennial Vine Wildflower From USDA PLANTS. Close