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DescriptionThis native perennial plant is 1-3' tall; it is unbranched toward the base, but branches occasionally in the upper half. The light green stems are glabrous and occasionally glaucous; they are slightly wider and angular at the base of the petioles. The compound leaves are trifoliate. The lower compound leaves have long petioles, while the upper compound leaves are sessile, or nearly so. There is an elongated membranous sheath at the base of the petioles. The leaflets of the compound leaves are up to 4" long and 2" across, becoming smaller as they ascend the stems. Each leaflet is ovate, elliptic or lanceolate in shape, doubly serrated along the margins, and hairless. Some leaflets may be shallowly to deeply cleft along their margins and have 1 or 2 lobes. Each leaflet is rounded or wedge-shaped at the base and it tapers to a winged petiole (i.e., a winged petiolule). The upper stems terminate in compound umbels of tiny white flowers. These umbels are somewhat irregular and span about 2-3" across. Each umbel divides into about 3-8 umbellets, while each umbellet consists of 3-10 flowers. Neither umbels nor umbellets have any significant bracts. Each flower is less than 1/8" across, consisting of 5 white petals, 5 white stamens, a conical pistil that is light green, and a tubular green calyx without teeth. Each petal usually curves inward at its tip. The blooming period occurs during early to mid-summer and lasts about a month. There is no noticeable floral scent. Each flower is replaced by an elongated ribbed seed that tapers at both ends. The seeds are initially green, but they later become dark-colored. The root system consists of a taproot. This plant spreads by reseeding itself; it occasionally forms colonies at favorable sites.