The Mimosa species of plants began as a creeping annual plant in Central and South America and is still often used as a ground cover.
The Mimosa pudica or Sensitive Plant is the variety most often grown as a houseplant.
The Sensitive Plant has prickly delicate branches and feathery fronds that fold inward and droop when they are touched, shaken, or even blown on; these are called seismonic movements.
The leaflets of a Sensitive Plant reopen in about half hour but fold up naturally each night. Although fun to watch, the opening and closing of the leaves weakens a Sensitive Plant if it occurs too often.
Mimosa Pudica may produce tiny pink flowers that resemble little fluffy balls, but this occurs more often when it is planted outdoors than indoors.