Cotinus obovatus Raf. (Smoke-tree) in Oklahoma

Abstract

Cotinus obovatus is a shrub or small tree, up to 6.5 m (20 feet) tall. The twigs are orange to brown, glabrous (without hairs), and aromatic when crushed (Figure 1). The sap is resinous and strong-smelling. The wood is yellow to orange in color with creamy colored sapwood. The leaves are alternate, simple, elliptical to obovate, 5-13 cm (2-5 inches) long, and 4-7.5 cm (1.6-3 inches) wide. They are pointed at the base, but rounded to weakly pointed at the apex and margins are entire. Leaves turn orange to scarlet in the fall (Figure 2). Flowers bloom in early spring, are very small, and have five petals and five sepals that are greenish in color, with five stamens and one pistil. Separate male and female flowers are present on the same plant. The wispy panicles measure 15 cm (6 inches) or more in length and are the root of the common name smoke-tree (Figure 3). However, there are few flowers in the panicle and many of them are sterile. Fruits are small drupes about 5 mm (0.2 in) in diameter. Some flowers are sterile and their stalks are long and covered with purplish or brownish hairs. The tree sprouts readily from the roots (Elias 1987, Hightshoe 1988, Kurz 1997, Little 1996, Sargent 1905).