(Return to Family List)
The Anacardiaceae is a mostly tropical family, but the temperate zone hosts the genera Rhus (sumac) and Toxicodendron (poison ivy, poison oak, and poison sumac). These genera consist of shrubs with alternate, usually trifoliolate or pinnately-compound, leaves, and irritating or milky juice. Poison ivy, poison sumac, and poison oak are all in the Anacardiaceae, but oddly enough, so are the plants from which we get mangoes, pistashios, and cashew nuts. The flowers generally have 5 sepals, 5 petals, 5 or 10 stamens that are borne on the edge of a disc that half encloses the ovary, and 3 styles. The ovary usually has a single seed and the fruit is a drupe.
|
|
POISON OAK Poison oak is an erect shrub (1-2 m or occasionally vining to 15 m) with trifoliolate leaves and oval to somewhat lobed leaflets. The leaflets are often glossy in summer and turn brilliantly red in the fall. The fruits are white or yellowish "berries" in a cluster. Most people are sensitive to the oil exuded by every part of this plant (including stems in winter), and skin contact causes water blisters and intense itching. The oil also can be transferred from dog fur to people and cause blisters. Washing the affected areas with soap and water immediately after contact can reduce the irritation. |