They don't have brains, they don't have arms or legs, and yet they can move, catch flies and other insects, draw back if you touch them, and can even vacuum. What are they?
Plants that move.
We are accustomed to associating movement with animals only.
Probably the best known of the moving plants is the carnivorous (L. caro or carnis, flesh, and vorare, to devour) Venus flytrap. The species name is Dionaea muscipula. Dionaea is new Latin from the Greek Dione, a name for Aphrodite, the goddess of love and beauty. Some writers believe muscipula means mousetrap, from the Latin mus for mouse; others believe it is from the Latin musca, for fly. This is a plant in which the two halves of the leaf blade have adapted as a bivalve trap adorned with spinelike projections along the outer edges. Nectar, secreted along the leaf edge, lures insects to the inner leaf surface. There are three sensitive hairs on the inner surface of each half. When an insect touches the hairs twice, a mild electrical current is generated. In less than a second, cells lengthen and the trap slams shut, entrapping the insect behind the spines.
Mimosa pudica is the sensitive plant, sometimes called humble plant. The genus Mimosa is named from the Latin mimicus and the Greek mimikos, for mime, because some species of this genus seem to wilt when touched. Pudicus is Latin for shy, modest, chaste, or to be ashamed. The leaves of M. pudica are compound, being composed of tiny leaflets, each of which has a water supply. What is the process by which Mimosa pudica withdraws from human touch? This takes place because a touch produces a sudden imbalance in the water supply. It may take only a second to collapse, but its recovery may take hours.
We come to the bladderwort, Utricularia. In Latin utriculus is a small bottle, which here refers to the tiny creature-trapping bladders produced on the leaves of these submerged aquatic plants. Each bladder is about the size of a pinhead, and there are dozens along each leaf. The bladder has a trap door. When the door is closed, the plant removes the water, so it becomes air-filled. At the entrance are tiny sensitive hairs. A minute, swimming prey touches a hair, the door swings back, and the prey is sucked by the vacuum into the bladder, with the door slamming behind. In the bladder the invertebrate prey are digested. Although many people have never even heard of the bladderwort, its statistics is startling. Species of bladderworts are numerically greater than any other carnivorous group. Found on all of the continents, with the exception of Antarctica, Utricularia is also the most widely dispersed. Its vacuum operates in as little as ten to fifteen one-thousandths of a second!
Moving right along, it's noon, and these plants have inspired me, so I am rushing out to grab a bite.
JULIE RASKOFF, MEMBG Docent