HEDYSARUM, in botany: A genus of the decadria order, belonging to the diadelphia class of plants; and in the natural method ranking under the 32d order, Papilionaceæ. The carina of the corolla is transversely obtuse; the feed-vessel a legumen with monospermous joints. There are 59 species of this plant, of which the most remarkable are, 1. The gyrans, or sensitive hedysarum, a native of the East Indies, where it is called burum chundalli. It arrives at the height of four feet, and in autumn produces bunches of yellow flowers. The root is annual or biennial. It is a trifolious plant, and the lateral leaves are smaller than those at the end, and all day long they are in constant motion without any external impulse. They move up and down and circularly. This last motion is performed by the twisting of the footstalks; and while the one leaf is rising, its associate is generally descending. The motion downwards is quicker and more irregular than the motion upwards, which is steady and uniform. These motions are observable for the space of 24 hours in the leaves of a branch which is lopped off from the shrub if it is kept in water. If from any obstacle the motion is retarded, upon the removal of that obstacle it is resumed with a greater degree of velocity. 2. The coronarium, or common biennial French honeyfuckle, hath large deeply striking biennial roots; upright, hollow, smooth, very branchy stalks, three or four feet high, garnished with pinnated leaves; and from between the leaves proceed long spikes of beautiful red flowers, succeeded by jointed feed-pods.
Culture. The first species being a native of hot climates, requires the common culture of tender exotics; the second is easily raised from seed in any of the common borders, and is very ornamental.