Some special plants are sensitive to touch.  Thigmonasty is the technical term for touch-induced movement in plants.

Sensitive brier (Mimosa quadrivalvis), so named for its thigmonasty, is in full bloom at the Oslo Riverfront Conservation Area, growing in full sun atop saw palmetto along the trail in the scrubby pine flatwoods.  Pink “powder puffs” about the size of a dime on long stalks adorn this diminutive, but entertaining, vine.  Take care when you touch the leaves for older stems are adorned with numerous hooked prickles as are the thin brown seed pods.  Devil’s shoelace is another common name for this plant.

The name of the genus of this plant, Mimosa, comes from the word, mimic, because of the movement of the leaves when touched.  The species name, quadrivalvis, means having four valves.  Sometimes this plant is called four-valve mimosa, since its prickled and flattened brown pods split longitudinally into four parts to disperse its tiny hard brown seeds.

You may be familiar with the mimosa tree (Albizia julibrissin), a short-lived exotic tree not recommended for planting in Florida due to its invaviseness, or with sunshine mimosa (Mimosa strigillosa), a native groundcover or lawn weed depending upon your proclivities.  These plants like sensitive brier are members of the pea or legume family, Fabaceae.  The pink powder puff flowers on these plants are an attractive nectar source for bees and other insects.  Sensitive brier is by far the most sensitive to touch.