Silphium perfoliatum var. connatum (L.) Cronq., is characterized by hairy stems with sessile leaves, and it occurs in scattered stations in the mountains and the adjacent piedmont of Virginia, West Virginia, and North Carolina. The more widespread typical variety, var. perfoliatum, ranges largely north and west of var. connatum (Gleason and Cronquist 1991).
Cup plant is primarily a prairie species, occurring in the eastern Great Plains from North Dakota to Kansas and Oklahoma, and ranging east to southern Ontario and south to North Carolina, Georgia, Arkansas, and Louisiana. The connatum variety is considered rare.
It is a robust, tall, perennial plant, commonly reaching 1 to 2 m or more in height. The stout, smooth to slightly hairy stem is strongly 4-angled and square in cross-section, bearing opposite, broadly ovate leaves with coarsely-toothed margins and roughened surfaces. The lower leaves
may be as large as 3 dm long and 1.5 dm wide, their bases uniting to form a distinctive cup encircling the stem. Branching above, the stem terminates in an open inflorescence with numerous heads of yellow flowers,each head composed of about 20-30 rays that are 1.5-3.5 cm long and disks that are from 1.5-2.5 cm in diameter.
This is quite the stunner in a colony. You are sure to love it if you enjoy large, robust plants.