A tree normally 30 to 40 ft high in the wild state, but taller in the rich alluvial soils of the Mississippi Basin; bark grey, rough, with warty excrescences; young branchlets glabrous or downy. Leaves ovate-lanceolate to broadly ovate, rounded or heart-shaped at the base, taper-pointed, 2 to 41⁄2 in. long, sharply toothed, smooth or scabrous above, downy on the midrib and the veins beneath. Fruit 1⁄3 in. across, globose, yellowish or reddish, finally dark purple when ripe, borne on a slender stalk 1⁄3 to 2⁄3 in. long
Native of the United States from the Atlantic to the Rocky Mountains, and of E. Canada. This tree is variable in regard to stature, foliage, form and colour of fruit, etc.; but these variations although great are not clearly correlated. East of the Appalachians it makes a small tree with broadly ovate leaves, more or less rounded at the base. This is the typical state, introduced in 1656. In var. canina (Raf.) Sarg., the leaves are more narrowly ovate and finely tapered at the apex. More distinct is:
var. cordata (Pers.) Willd. C. 0. var. crassifolia (Lam.) Gray – This is chiefly distinguished by its invariably downy young shoots, and its often heart-shaped, much larger leaves (2 to 6 in. long, 1 to 3 in. wide), very rough on the upper surface. In cultivation this is a vigorous tree, making arching or pendulous shoots several feet long in a season, clothed with big leaves sometimes as much as 7 in. by 41⁄2 in.
This variety is commonest west of the Appalachians. It also appears to be the form in which the species is most commonly seen in cultivation in Europe. It was introduced, according to Loudon, in 1812, but probably earlier.
C. pumila (Muhl.) Pursh C. occidentalis var. pumila Muhl. – A shrub or small tree to 15 ft high. Leaves smaller than in C. occidentalis, downy on both sides when young, later glabrous; margins almost untoothed. It ranges to the west (Colorado, Utah, etc.) and was introduced to Kew from the Arnold Arboretum in 1905.
From the Supplement (Vol. V)
[C. pumila] – The correct name for the species once considered to be the C. pumila of Pursh is C. tenuifolia Nutt. It is a shrub or small tree. Leaves of thinnish texture, entire or almost so except on strong shoots, ovate or oblongovate, up to about 31⁄2 in. long, short-acuminate or acute at the apex. Fruits smaller than in C. occidentalis, 1⁄4 to 3⁄8 in. wide, spherical, usually red or orange. Native of the southern and central USA. There are several examples at Kew. C. tenuifolia var. georgiana (Small) Fern. & Schubert differs in its thicker leaves somewhat scabrous above.
The true C. pumila Pursh is a form or variety of C. occidentalis, differing from the typical state not so much in its dwarf as in its thinner, smooth leaves and in its differently shaped and differently coloured fruits. The species itself sometimes occurs in a dwarf form.