=Albízzia julibríssin=, Boivin. (SILK-TREE.) Leaves twice abruptly pinnate, of many (over 400) leaflets; leaflets semi-oblong, curved, entire, acute, with the midrib near the upper edge. Flowers in globose heads forming panicles. Fruit plain pods on short stems. A very beautiful small tree, introduced from Japan; probably not hardy north of Washington. The figure shows only one of the lowest and shortest side divisions (pinnæ) of the leaf. The pinnæ increase in length and number of leaflets to the end of the leaf. ORDER =XVIII. ROSACEÆ.= (ROSE FAMILY.) A large and very useful order of trees, shrubs, and herbs of temperate regions. GENUS =36. PRÙNUS.= Trees or shrubs with simple, alternate, deciduous, usually serrate, stipulate leaves, without lobes. The stems produce gum when injured. Foliage and nuts have flavor of peach-leaves. Flowers conspicuous, usually white, or light pink, often in clusters, peach-blossom-shaped; in early spring. Fruit in size from pea to peach, a rounded drupe with one stony-coated seed. * Drupe large, soft velvety on the surface; stone rough (Peach, Apricot) 1. * Drupe medium, covered with a bloom; stone smooth, flattened (Plums). (=A.=) =A.= Usually thorny; wild, rarely cultivated. (=B.=) =B.= Leaves acuminate 2, 3. =B.= Leaves not acuminate 4, 5. =A.= Not thorny; cultivated 6. * Drupe medium to small, smooth, without bloom (Cherries). (=C.=) =C.= Drupes clustered in umbels, ½-1 in. in diameter. (=D.=) =D.= Small cultivated tree; drupe globose, rather large, very sour 9. =D.= Large cultivated tree; drupe large, somewhat pitted at the stem 8. =D.= Rather small, native tree; drupe small, flesh thin 7. =C.= Drupes clustered in racemes, 1/8 - 1/3 in. in diameter. (=E.=) =E.= Tall shrubs rather than trees; racemes short 11. =E.= Trees; racemes quite elongated. (=F.=) =F.= Stone of fruit somewhat roughened 12. =F.= Stone smooth 10. [Illustration: P. Pérsica.] 1. =Prùnus Pérsica=, L. (COMMON PEACH.) Leaves lanceolate, serrate. Flowers rose-colored, nearly sessile, very early in bloom. Fruit clothed with velvety down, large; stone rough-wrinkled. A small tree, 15 to 30 ft. high, cultivated in numberless varieties for its fruit. Var. _lævis_ (Nectarine) has smooth-skinned fruit. [Illustration: P. Americàna.]