Plant 2 to 6 feet tall.  Leaves alternate on the stem.  Each leaf is compound, with 10-20 leaflets, each about 1 to 2 inches long, oblong, with smooth margins, and a tiny needle-like tip.  At the base of each leafstalk are 2 tiny hairs called stipules (middle right), and a little ball on a stalk, called a gland (lower, left), Flowers in a large cluster at the top, about an inch across.  The structure of the flower is complex.  There are 5 yellow sepals in back, and 5 yellow petals, 3 sticking up, and 2 spreading to the side.  In the middle there are 10 yellow stamens with black anthers that produce pollen.  The stamens are in 3 rows and 3 sizes.  Five small stamens at the top, 3 medium stamens below them, and 2 long stamens at the bottom.  Below all that is a long, green, hairy pistil with a black pollen-receiving tip.  Fruits are legumes, green, turning brown when mature, divided into 10-18 squarish segments that burst open and release the seeds.

Native to eastern North America from Ontario to Georgia.  It likes open, moist meadows, pastures and roadsides. A couple of plants have appeared in Wildwood (in 2019), near the base of the Grand Staircase.  It is a long-lived perennial, so hopefully it will persist and reproduce.

Maryland Senna (Senna marilandica) is very similar, and is native to our area.  Maryland Senna has short hairs on the pistil, while Wild Senna has long, spreading hairs.  Maryland Senna seedpods are divided into short, not square, segments, and do not burst open when ripe.  The gland of Maryland Senna is more round or dome-shaped while that of Wild Senna is stalked.  Finally, Maryland Senna prefers dry rocky woods, over the moist sites that Wild Senna likes.