A tree 100 to 120 ft high; bark separating from the trunk into broad plates often 3 or 4 ft long; young shoots at first downy; terminal winter bud 1 in. long. Leaves 12 to 22 in. long, composed of usually seven, sometimes nine, leaflets, the terminal ones of which are obovate, 4 to 8 in. long, 11⁄2 to 21⁄2 in. wide, the lower ones ovate and only one-third or one-fourth the size; all long and slender-pointed, toothed; glabrous, and glossy above, downy beneath. Male catkins 4 in. or more long. Fruit oblong, 21⁄2 in. long, 2 in. wide; nut four- or six-ridged.
Native of the eastern United States from New York and E. Pennsylvania southwards; introduced to England in 1804. The tree in Tortworth churchyard, Glos., mentioned in previous editions, now measures 60 × 5 ft (1964 – 30 × 13⁄4 ft in 1905); no other sizeable specimen has been recorded. This species resembles the better-known C. ovata but usually has seven not five leaflets, which are downy beneath (glabrous in C. ovata). It resembles C. tomentosa in having leaves with usually seven leaflets, hairy beneath, but in that species the indumentum is woolly and persistent (merely downy in C. laciniosa) and glands are also present; also the bark of C. tomentosa is close, not shaggy, and the terminal winter buds are broadly ovoid (almost globose).
From the Supplement (Vol. V)
In the first printing of the current edition it was stated that no sizeable specimen of this species had been recorded other than the one in Tortworth churchyard. This is no longer the case:
specimens: Osterley Park, Middx., in Woods (N), 80 × 51⁄4 ft (1976); Blackmoor, Hants, 70 × 5 ft and 70 × 4 ft (1982); Wakehurst Place, Sussex, 95 × 31⁄2 ft (1984); Nymans, Sussex, 80 × 41⁄4 ft (1985); Borde Hill, Sussex, pl. 1913, 75 × 33⁄4 ft (1976); Tortworth Church, Glos., 56 × 51⁄4 ft (1973); Bicton, Devon, 72 × 4 ft (1983); Enys, Cornwall, 72 × 41⁄2 ft (1977); Madresfield Court, Worcs., 65 × 41⁄2 ft (1975).