1. Rhus aromatica Aiton (fragrant sumac, aromatic sumac)

Pl. 200 a, b; Map 831

Plants shrubs. Stems 0.5–1.5 m long, erect or ascending. Branches nearly glabrous to densely hairy, aromatic when bruised. Leaves trifoliate, the petiole 1.0–2.5 cm long. Leaflets variable in shape and lobing, nearly glabrous to densely pubescent, the terminal leaflet sessile, broadly ovate to rhombic, 4–9 cm long, 2–8 cm wide, scalloped or toothed near the tip, entire and angled at the base. Inflorescences terminal, small panicles with spicate branches, 2–6 cm long, 1–3 cm wide, the branches occasionally relatively small and appearing as dense clusters of flowers. Flower stalks 1–3 mm long. Sepals lanceolate, 1.0–1.4 mm long, 0.3–0.4 mm wide, broadly rounded at the tip, the surfaces glabrous, reddish brown, the margins with nonglandular hairs. Petals oblong-obovate, 1.6–2.5 mm long, rounded at the tip, glabrous or hairy on the inner surface, yellow. Fruits 5–7 mm long, 4–6 mm wide, red, slightly flattened, pubescent with dense, minute, stout, red glandular hairs and sparse to dense, white to colorless nonglandular hairs. 2n=30. March–May.

Scattered to common throughout the state (eastern U.S. west to South Dakota and Texas; Canada). Glades, tops of bluffs, savannas, and openings of mesic to dry upland forests; also old fields and roadsides.

The species of Rhus with flowers in spikes sometimes have been treated separately from those with flowers in a terminal panicle, as the genus or subgenus Schmaltzia. The trifoliate-leaved species at times have been placed in Lobadium, which is now considered a section of Rhus. Barkley (1937) recognized four species of Rhus with trifoliate leaves and reddish fruits, which he separated on the basis of overall size, length of the bracts, shape and size of the leaflets, relative pubescence, length of the flower stalks, and time of flowering relative to leaf emergence. Two of these are found in the United States: R. aromatica in the eastern portion of the country, and R. trilobata in the Great Plains region and farther west. The transition from one species to the other occurs in a broad region that includes Missouri, Arkansas, Oklahoma, and Kansas. Numerous varieties and combinations in both R. aromatica and R. trilobata have been proposed, but there is general agreement that a careful biosystematic study of the entire complex is needed before any of these names can be applied with confidence.

The fruits of both R. aromatica and R. trilobata sometimes are steeped in hot water to make a pleasant beverage with a somewhat lemony flavor. However, because these species contain trace amounts of the same chemical substances that are produced more abundantly in Toxicodendron, a very small percentage of individuals who are hypersensitive to urushiols develop a strong allergic reaction to drinking the tea.