Betula lutea Michx.

A tree up to 100 ft high in a wild state; bark of the trunk yellowish brown when newly revealed by the curling back of the outer layer; young wood more or less hairy the first summer. Leaves dull green, ovate or ovate-oblong, 21⁄2 to 41⁄2 in. long, half as wide; tapered, rounded, or heart-shaped at the base, pointed, doubly toothed; hairy on the margin, midrib, and chief veins, becoming glabrous above by the end of the season; veins in nine to twelve pairs. Fruiting catkins 1 to 11⁄2 in. long, erect, 3⁄4 in. thick; scales conspicuously downy on the outside and margins, the lobes about equal size, oblong. The young bark has a bitter taste.

Native of eastern N. America; introduced in the latter half of the eighteenth century. It is a handsome birch, and might be more extensively planted. It is distinct in the colour of the newly exposed bark of the trunk. It is sometimes confused with B. lenta, under which the distinctions are pointed out.

This species is variable in the size and degree of downiness of the fruit-scales. Trees in which the scales are markedly long (more than 1⁄3 in.) are sometimes distinguished as var. macrolepis Fern.

In cultivation in the British Isles B. lutea has attained a height of around 45 ft. There are specimens of this size at Lanarth, Cornwall; Westonbirt, Glos.; and in other collections. The example at Kew, pl. 1934, measures 40 × 21⁄2 ft (1967).

From the Supplement (Vol. V)

It was pointed out by E. L. Little in 1957, in his Check List, that the name B. lutea Michx. f. is illegitimate. In describing the yellow birch in 1814 the younger Michaux cited the earlier name B. excelsa Ait. as a synonym, altering the epithet to lutea most probably because he considered Aiton’s choice of epithet to be inappropriate for a comparatively small tree. If Aiton’s B. excelsa was indeed the yellow birch, this would be the correct name for it, and it was in fact used by some authorities, for example by Loudon in Arb. et Frut. Brit., Vol. 3, p. 1707. As it happens, B. excelsa Ait. is not the yellow birch and remains of uncertain identity. It is therefore necessary to go forward in time to find a valid name, and this is B. alleghaniensis Britton. This overthrow of the well-established name B. lutea is regrettable, but the name B. alleghaniensis is used in recent American works, so it would be futile now to resist the change.