1. =Plánera aquática=, Gmel. (AMERICAN PLANER-TREE.) Leaves ovate-oblong, small, 1 to 1½ in. long, on short stems, sharp-pointed, serrate with equal teeth, smooth, green above and gray below, not oblique at base. Flowers minute, in small heads, appearing before the leaves. Fruit a scaly, roughened nut, ¼ in., raised on a stalk in the calyx; ripe in September. A small tree, 20 to 50 ft. high; wet banks, Kentucky and southward; hardy as far north as Philadelphia. [Illustration: P. acuminàta.] 2. =Plánera acuminàta.= (KIAKA ELM OR JAPAN PLANER-TREE.) Leaves large, glossy, smooth, deeply notched, on red stems; young shoots also red. This is a larger, more hardy, and finer tree than the American Planer-tree, and should be more extensively cultivated. The Caucasian Planer-tree (_Planera parvifolia_), with very small leaves, is also occasionally cultivated. GENUS =76. CÉLTIS.= Trees or shrubs with alternate, simple, 2-ranked, oblique, serrate leaves. Flowers inconspicuous, greenish, axillary. Fruit berry-like, sweet, edible drupes, about the size of a currant, with one seed; color dark; ripe in autumn. * Leaves usually sharply serrate 1. * Leaves almost entire 2. [Illustration: C. occidentàlis.] 1. =Céltis occidentàlis=, L. (SUGARBERRY. HACKBERRY.) Leaves ovate, obliquely subcordate to truncate at base, long-acuminate, serrate (at least near the apex), rough above and hairy beneath. Fruit a single-seeded, ¼ in., globular drupe, solitary on a peduncle, 1 in. long, in the axils of the leaves; purple when ripe in autumn. Shrub (var. _pumila_) to large tree, 6 to 50 ft. high; throughout; rare north, abundant south. Sometimes cultivated. The branches are numerous, slender, horizontal, giving the tree a wide-spreading, dense top. [Illustration: C. Mississippiénsis.] 2. =Céltis Mississippiénsis=, Bosc. Leaves almost entire, with a very long, tapering point, a rounded and mostly oblique base, thin and smooth. Fruit smaller than that of the preceding species. A small tree with rough, warty bark. Illinois and southward. GENUS =77. MACLÙRA.= Trees or shrubs with milky juice and simple, alternate, entire, deciduous leaves, generally having a sharp spine by the side of the bud in the axils. Flowers inconspicuous; in summer. Fruit large, globular, orange-like in appearance. [Illustration: M. aurantìaca.] =Maclùra aurantìaca=, Nutt. (OSAGE ORANGE. BOW-WOOD.) Leaves rather thick, ovate to ovate-oblong, almost entire, smooth and shining above, strong-veined and paler beneath, 4 in. long by 2 in. wide; spines simple, about 1 in. long. Fruit as large as an orange, golden-yellow when ripe. A medium-sized tree, 20 to 50 ft. high; native west of the Mississippi. Extensively cultivated for hedges, and also for ornament, throughout. GENUS =78. MÒRUS.=