1. Castanea dentata (Marshall) Borkh. (American chestnut)

Pl. 413 h–k; Map 1835

Plants trees to 30 m tall (mostly much shorter now). Bark gray, deeply furrowed. Twigs very dark brown, with sessile glands, otherwise glabrous. Buds with the outer pair of scales brown or purplish, glabrous or sparsely and minutely hairy. Leaves with the petiole 13–22 mm long, glabrous or with a few long spreading hairs, also with very inconspicuous, sessile glands. Stipules lanceolate, shed early. Leaf blades 12–23 cm long, 4.5–7.5 cm wide, narrowly elliptic, rounded or broadly angled at the base, long-tapered at the tip, the marginal teeth 2–4 mm long, slenderly tapered, often hooked, the secondary veins 16–20 on each side of the midvein, both surfaces with the main veins glabrous or with a few long spreading hairs, also with very inconspicuous, sessile glands. Cupules 1–4 per spike, 3–4 cm wide at fruiting (excluding the spines), splitting into 4 valves, the spines 15–20 mm long. Nuts 2 or 3 per cupule, 18–25 mm long, flattened on 1 or 2 sides. 2n=24. May–July.

Introduced, uncommon in eastern Missouri west locally to Howell County (eastern U.S. west to Wisconsin and Louisiana; introduced farther west). Mesic upland forests near old homesites; also margins of pastures and power line corridors.

American chestnut was once a dominant tree in mesic forests in the Appalachians. Its wood is strong and easily worked, and it was one of the most important timber trees in the eastern United States. It is highly susceptible to the chestnut blight, and trees have been killed to the ground in virtually all parts of its native range. Sprouts from surviving root systems are still commonly found in areas where the trees once grew, but these sprouts seldom survive long enough to flower and set seed, so the species is gradually dying out. Missouri is outside the native range of C. dentata, and it is known in the state only from a few escapes.