Dionaea (D. muscipula, Ellis), Venus's flytrap, an insectivorous plant inhabiting the savannas around Wilmington, N. C, and only found in that district. Audubon's affirmation that he had seen it in Florida of enormous size is not confirmed. It belongs to the same natural order as the droseras, or sundews, the common species of which capture flies as effectually as dionaea, but by a different contrivance. It was discovered by the elder Bartram, sent to Collinson, and well described by Ellis in a short treatise addressed to Linnaeus. The brief account given by the latter, which was generally copied till recently, was wrong in stating that the trap opens after an insect it has caught becomes quiet; it does not open until all the soft parts of the insect are extracted. To aid in this, a glairy liquid is secreted from innumerable glands which stud the face of the trap, which after maceration of the captive is reabsorbed. The plan and action of the trap may be gathered from the cut and a few words of description, partly condensed from the account of Dr. M. A. Curtis ("Journal of the Boston Society of Natural History," 1834). The trap, at the apex of the leaf, is fringed with stout bristles on each margin; it is aptly compared to two upper eyelids joined at their bases.

On each side are three more delicate bristles, so directed that an insect can hardly traverse it without touching one of them, when the two sides suddenly-close upon the prey, the fringe of the opposite sides interlacing, like the fingers of the two hands clasped together. The sensitiveness resides only in these hair-like processes on the inside, as the leaf may he touched or pressed in any other part without effect. Soon the sides of the trap press down firmly upon the captive (when the fringe separates); the liquid is poured out, and finally absorbed, when the trap opens, and sometimes recovers its activity so as to capture a second insect. Ellis (and probably Bartram) noticed the glands and the fluid, but thought it was a lure for flies. Curtis showed that it appeared only after the capture. Canby lately proved that it was secreted by the leaf, and taken in again; also that bits of meat were similarly digested. Darwin had ascertained the same, also that this "gastric juice" had an acid reaction. He has also made the (still unpublished) discovery that either side of the trap may be paralyzed at will by a dexterous incision, indicating the existence in a plant of something corresponding to nerves.

Burton Saunderson has shown that in the closing movement the same electrical currents are developed as in muscular contraction.

Dionaea muscipula.