This species bears very small flowers, on short pedicels, similar in shape and size to the last. Leaflets, 10 to 20 pairs, oblong to linear, sensitive, with a gland at the base of the petiole.
Shelley's famous poem, "The Sensitive Plant," refers to the Mimosa pudica, a European plant, whose leaves are more sensitive than those of our cassias. All of this genus fold their leaflets and "sleep" at night. In the partridge pea each pair folds together, and they then lie along their main stem, flattening themselves closely against it, so as scarcely to be distinguishable at night from the branches.
Wild sensitive plant (Cassia nictitans)
"A sensitive plant in the garden grew, And the young winds fed it with silver dew; And it opened its fan-like leaves to the light, And closed them beneath the kisses of night."
The leaves of our species are feather-like rather than fan-like.
These plants are common from New Jersey and Long Island southward. In their season they make bright with color the dry land along the railroads, extending into the fields and lining the waysides. (See illustration, p. 178.)