3. Rhus glabra L. (smooth sumac)

Schmaltzia glabra Small

Pl. 201 a–c; Map 833

Plants large shrubs or rarely small trees. Stems 2–5 m tall, ascending. Young branches glabrous, glaucous (but note that inflorescence branches usually are sparsely hairy), the older branches usually with prominent lenticels. Leaves pinnately compound with 11–21 leaflets, the petiole 6–11 mm long, glabrous, reddish purple, the rachis not winged. Leaflets 5–13 cm long, 1.5–3.0 cm wide, lanceolate to elliptic-lanceolate, sessile or very short-stalked, the margins toothed, the upper surface dark green, glabrous, shiny, the undersurface light green, glabrous, glaucous. Inflorescences terminal, dense, ovoid panicles, 10–25 cm long, 5–10 cm wide. Sepals 1.6–2.0 mm long, narrowly ovate, sharply pointed at the tip. Petals 2.0–2.5 mm long, oblanceolate, rounded at the tip, greenish yellow, sparsely hairy on the inner surface. Fruits 4–6 mm long, 4–5 mm wide, somewhat flattened, red, with dense, minute, stout, red glandular hairs. May–June.

Scattered nearly throughout the state (U.S., Canada, Mexico). Open woods, brushy areas along roadsides, railroads, and fencerows.

This species has been investigated as a potential source of tannins and oils (Campbell, 1984). It is too aggressive for most home gardens, but a cut-leaved cultivar, f. laciniata (Carr.) B.L. Rob., apparently is less aggressive and sometimes is cultivated. Steyermark (1963) mentioned the northern var. borealis Britton with somewhat hairy branches, but this is now considered a putative hybrid between R. glabra and R. typhina and treated as R. ×borealis (Britton) Greene. Because R. typhina is rare in Missouri, it is unlikely that this hybrid will be recorded from the state in the future.