4. Rhus typhina L. (staghorn sumac)
R. hirta (L.) Sudw.
Pl. 201 d; Map
shrubs or small trees 2–6 m tall, with stout branches. Young branches,
petioles, and leaf rachis densely pubescent with woolly or felty hairs. Leaves
pinnately compound, with 9–25 leaflets, rarely 2 times pinnately
compound, 9–40 cm long, the petioles 3–10 cm long, densely
woolly or felty, the rachis not winged. Leaflets 7–10 cm long,
1.0–4.5 cm wide, (appearing dissected in bipinnate forms), lanceolate
to narrowly oblong, sessile or very short-stalked, the margins toothed, the
upper surface dark green, glabrous or nearly so, shiny, the undersurface light
green, moderately to densely hairy along the veins, also glaucous.
Inflorescences terminal, dense, ovoid panicles, 7–25 cm long,
3–4 cm wide. Sepals 1.2–1.5 mm long, narrowly ovate, sharply
pointed at the tip. Petals 1.5–2.5 mm long, oblong-oblanceolate,
rounded at the tip, greenish yellow, sparsely hairy on both surfaces. Fruits
4–5 mm long, 4–5 mm wide, somewhat flattened, red, with dense,
slender, straight, red hairs 1–2 mm long. 2n=60.
known thus far from Greene County and the St. Louis metropolitan area (eastern
U.S. west to Wisconsin and Mississippi, introduced farther west; Canada).
Railroads and open, disturbed areas.
The name R.
typhina L. is widely used and deeply entrenched in the botanical
literature, but for a time it appeared that, as a consequence of a minor change
in wording in a past International Code of Botanical Nomenclature, an older
name, R. hirta, might have to be used for this taxon (Reveal, 1991b;
Kartesz and Gandhi, 1991). The basis for this name, Datisca hirta L.,
was based upon a monstrous cultivated form of the species in which the
inflorescence had reverted to leaves. Fortunately, that epithet was rejected
formally from any further use at the 1999 International Botanical Congress in
St. Louis (Greuter et al., 1999), thus stabilizing the use of the name R.
reports of this species in Missouri were of escaped plants of R. typhina
f. dissecta Rehder (var. laciniata A.W. Wood), a cultivar with
dissected, 2 times pinnately compound leaves that is sometimes planted as an
ornamental in gardens.