Rubber tree
From Memory Alpha, the free Star Trek reference
The rubber tree (Hevea brasiliensis) is a woody plant native to Earth, so named because it produces a substance that can be made into natural rubber.
In one of the stories in The Adventures of Flotter children's holonovel series, Flotter suspects Trevis is a rubber tree, so he keeps trying to trip him to see if he would bounce. (VOY: "Once Upon a Time")
