The Leaf Dimorphism of Liquidambar styraciflua L.

In Liquidambar styraciflua each twig produces two kinds of leaves; the first leaves to form in the early spring are relatively shallow-lobed, the late leaves are more deeply lobed and generally have shorter petioles. Seedlings do not have two forms of leaves. Secondary branches on a given year's growth always have late, deeply lobed leaves. The early leaves are from the overwintering bud; the late leaves are produced directly from the apical meristem without overwintering, as leaf primordia. Phenology is given for one season. No evidence was found showing that the second form of leaf was associated with a second spurt of stem growth. The two forms of leaves might be selectively advantageous for sweet- gum; the late leaves are probably more drought resistant.