3. Euonymus atropurpureus Jacq. (wahoo, spindle tree)

Pl. 351 h–j; Map 1506

Plants erect or ascending shrubs or small trees with ascending or spreading branches, 2–6 m tall. Twigs green, gray, or less commonly brownish purple, circular in cross-section. Leaves relatively thin and herbaceous, deciduous, short-petiolate, the petiole 10–20 mm long. Leaf blades 4–14 cm long, 2–7 cm wide, elliptic to narrowly ovate or ovate, narrowed or tapered at the base, narrowed or tapered to a usually sharply pointed tip, the margins finely and usually sharply toothed. Inflorescences small axillary panicles with 6–24 flowers. Sepals 4, 1.0–1.5 mm long. Petals 4, 2–3 mm long, 1.5–2.5 mm wide, ovate to broadly ovate, dull purple to brownish purple, the margins often thinner, pale, and slightly irregular. Fruits 6–10 mm long, 2–4-lobed from the tip to about the midpoint, the valves smooth, pink to purple, fading to tan. Seeds 1–6 per locule, 4–5 mm long. 2n=32. April–June.

Scattered nearly throughout the state (eastern U.S. west to Montana and Texas; Canada). Bottomland forests, mesic upland forests, bases and ledges of bluffs, banks of streams and rivers, and margins of glades, upland prairies, and loess hill prairies; also pastures, railroads, and roadsides.

This species is recognized by the relatively long petioles, large compound inflorescences, and smooth, rosy-red capsules.

Euonymus europaeus L., the European spindle tree, is sometimes cultivated in Missouri and can persist at old homesites. Although the label on a specimen from St. Louis County indicates the potential for localized spread, this species has yet to be documented as fully established and reproducing outside cultivation in the state. Euonymus europaeus would key to E. atropurpureus in the key to species above but differs in its totally glabrous (vs. often sparsely hairy) leaves that are often larger (to 15 cm long), as well as its fewer-flowered inflorescences (3–8 flowers), greenish white corollas, and seeds with a more orange aril. This native of Europe has become naturalized sporadically in the eastern United States.