Flower:

Large open, branching clusters of short-stalked flowers arising from the leaf axils of 1-year-old branches, with male and female flowers usually on separate plants, sometimes the same plant. Flowers are less than ¼ inch across with 5 creamy to greenish white petals. Male flowers have 5 yellow-tipped stamens; female flowers have a 3-parted style in the center. The calyx cupping the flower has 5 pointed lobes about as long as the petals. Flower stalks and the calyx are smooth or variously covered in short hairs.

Leaves and stems:

Leaves are alternate, up to 12 inches long, compound with 7 to 13 leaflets. Leaflets are generally oval-elliptic, 2 to 3½ inches long, 1 to 1½ inches wide, toothless, mostly hairless, with an abrupt short taper to a pointed tip, and tapering at the base. The tip leaflet has a stalk up to 1 inch long, lateral leaflets are stalkless or nearly so; the upper surface is dark green, the lower paler in color. Leaf stalks are hairless and often reddish. Leaves turn bright orange to red in fall.

Twigs and branches are brown and hairless, older bark is light gray and smooth, or rough from large horizontal lenticels (pores). Stems are up to 2 inches in diameter at breast height (dbh).

Fruit:

The female flower clusters form loose, dangling clusters of round, smooth, berry-like drupes, each less than ¼ inch in diameter and containing a single seed. Fruit ripens to dull yellowish white and may persist through winter.

Notes:

Poison Sumac, formerly known as Rhus vernix,  gives a bad rap to other native Sumacs, making many Minnesotans avoid all Sumacs in fear of severe, itching rash. It is indeed poisonous, reputedly much more severe than Poison Ivy (Toxicodendron rybergii and T. radicans), but, however, restricted to swamps and other wet places in Minnesota's east central counties, so rarely likely to be encountered by the average day hiker. It is easily distinguished from “safe”—and in fact quite edible—Sumacs by its toothless leaflets and more so by its creamy, hanging fruit clusters as compared to the serrated leaflets and bright red, erect clusters of our other Sumac species.

Several interesting observations on this species. A nursery grower near Forest Lake had landscaped his lake front with numbers of them, himself being immune to their toxicity. When I asked about his grandchildren that were about, he only noted that he had given his warning and they had better learn to respect nature one way or the other - wisdom in a clueless, over-protective age? On another occasion while exploring Boot Lake SNA in Anoka County, I came across numbers of marijuana plants in Menard's five gallon pails tucked away into the centers of poison sumac clumps. While I doubt it would have stopped the DEA, the local entrepreneur no doubt had some notion of vengeance on their mind!