shrub-trefoil: A genus of the mongynia order, belonging to the tetrandria class of plants; and in the natural method ranking with those of which the order is doubtful. The corolla is tetrapetalous; the calyx quadripartite inferior; the fruit is monospermous, with a roundish membrane in the middle. The species are, 1. The trifoliata, or Carolina shrub-trefoil, hath a shrubby upright stem, dividing into a branchy head eight or ten feet high, covered with a smooth purple bark, trifoliate leaves, formed of oval spear-shaped folioles, and the branches terminated by large bunches of greenish-white flowers, succeeded by roundish, bordered capsules. 2. The viciaea, or viscous Indian ptelea, rises with several strong shrubby stems, branching erectly 12 or 15 feet high, having a light brown bark, spear-shaped, stiff, simple leaves, and the branches terminated by clusters of greenish flowers.

The first species is a hardy deciduous shrub, and a proper plant for the shrubbery and other ornamental plantations to increase the variety. It is propagated by seeds, layers, and cuttings.

The second species is a stove-plant, and is propagated commonly by seeds.