The flowers are borne in clusters on slender stems diverging from the axis of the leaf, as may be noted in [figure 17], C. The individual flowers are greenish white and about one-fourth inch across. The cluster of flowers matures into greenish or creamy-white berrylike fruits about mid-October. These are about the size of small currants and are much like other poison-ivy fruits, having a smooth greenish-white glossy surface striped somewhat like the segments of a peeled orange. Many plants bear no fruit, although others produce it in abundance, as shown in [figure 18, A]. The fruits are not always spherical, but sometimes have a somewhat flattened appearance, as is shown in [figure 18, B]. They remain on the plants throughout fall and winter and are quite helpful in identifying poison-oak in seasons after the leaves have fallen.
[POISON SUMAC]
Figure 21.—Small branch of poison sumac with six compound leaves.
Poison sumac grows as a coarse woody shrub or small tree ([fig. 19]) and never in the vinelike form of its poison-ivy relatives. This plant is known also as swamp sumac, poison elder, poison ash, poison dogwood, and thunderwood. It does not have variable forms, such as occur in poison-oak or poison-ivy, and botanists agree to call it Rhus vernix. The area in the Eastern States where it is likely to be found is chiefly eastward from eastern Minnesota, northeastern Illinois, Indiana, central Kentucky and Tennessee, and southeastern Texas, as shown on the shaded area of the map, [figure 20]. This shrub is usually associated with swamps and bogs, and the most typical growth occurs along the margin of an area of wet acid soil.