3. Rhus glabra L. (smooth sumac)
a–c; Map 833
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.
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.