Sensitive plants are so named because they have a very unusual property: they fold up
when touched. Well usually. Sometimes they don’t, and sometimes they respond slowly.
It is native throughout most of the Americas. It prefers rocky open woods,
upland slopes, ridges, prairies, grasslands, and open thickets.
Plants: 1-3′ (30-91 cm) tall, often low to the ground, sometimes forming large mats.
Leaves: Even pinnate. Each leaf has 8-18 pairs of
narrow leaflets about ⅝″ (1.7 cm) long. Leaves fold when touched, or at night.
Flowers: Yellow, 5-petaled, 1″ (2.5 cm) around, either separate or in clusters of 2-3. Petals are unequal in size and shape. There are 5-10 stamens. Flowers appear August through October.
Fruits: Shaped like pea pods, highly variable,
¾-1½″ (2-4 cm) long. When they dry, they turn brown and explode, scattering seeds.