1. Carpinus caroliniana Walter (blue beech, hornbeam, musclewood)

Pl. 303 h, i; Map 1277

Plants small trees 4–10 m tall, the bark smooth. Young growth not sticky or resinous. Twigs about 1 mm thick, medium to dark brown, pubescent with appressed or spreading hairs, the buds sessile, with more than 10 scales. Petioles 6–13 mm long. Leaf blades 5–10 cm long, 2.0–4.5 cm wide, narrowly elliptic to narrowly ovate or obovate, the undersurface green, pubescent with scattered long, weak hairs, smooth or slightly felty to the touch, the tip narrowed or tapered to a sharp point, the base broadly narrowed or rounded to weakly cordate, the margins sharply toothed to the base, the lateral veins 10–16 on each side of the midrib, rarely branched. Stamens 3, each divided almost to the base. Fruits nutlets (mostly 2 or 3 per flower), 2–5 mm long, 2–5 mm wide, ovoid, somewhat flattened, the shell thin, longitudinally veined, brown, arranged in elongate spikes with mostly 10–20 nutlets. Bracts 18–27 mm long, fused into a relatively flat structure, deeply lobed, herbaceous, strongly veined, green, bluntly lanceolate or narrowly oblong with 1 or more short basal lobes, sparsely hairy primarily on the veins, bracts not concealing the nutlets but falling with them. 2n=16. March–May.

Scattered nearly throughout the state, but uncommon in the Glaciated Plains Division and apparently absent from the Unglaciated Plains (eastern U.S. west to Minnesota and Texas; Canada). Bases and ledges of sheltered bluffs, banks of streams and rivers, margins of sinkhole ponds, and mesic upland forests in ravines.

The trunks of C. caroliniana are usually conspicuously fluted, a feature that is made more apparent by the smooth, light gray bark. Their form is reminiscent of the limbs of a sinewy, muscular person, hence the common name musclewood. The species performs well as a landscape plant and is becoming common in the nursery trade. The wood is almost as hard and strong as that of Ostrya virginiana and has been put to similar uses, but as with the latter species, its usefulness is limited by the small size of the trees.