8. =Prùnus àvium=, L. (BIRD-CHERRY OR ENGLISH CHERRY.) Leaves oval-lanceolate, sharp-pointed, coarsely or doubly serrate. Flowers in sessile umbels, opening when the leaves appear. Fruit of various colors, somewhat heart-shaped. This is the Cherry tree, 30 to 50 ft. high, of which there are many named varieties usually cultivated for the fruit. [Illustration: P. Cérasus.] 9. =Prùnus Cérasus=, L. (GARDEN RED CHERRY. MORELLO CHERRY.) Leaves obovate and lance-ovate, serrate, on slender spreading branches. Flowers rather large. Fruit globular, bright red to dark purple, very sour; in sessile umbels. A small, round-headed tree, 10 to 30 ft. high, often cultivated. The preceding species and this one are the parents of most of the Cherry trees in cultivation. [Illustration: P. serótina.] 10. =Prùnus serótina=, Ehrh. (WILD BLACK CHERRY.) Leaves oblong or lance-oblong, thickish, smooth, usually taper-pointed, serrate, with incurved, short, thick teeth. Flowers in long racemes. June. Fruit as large as peas, purple-black, bitter; ripe in autumn. A fine tree, 15 to 60 ft. high, with reddish-brown branches. Wood reddish and valuable for cabinet-work. Common in woodlands and along fences. [Illustration: P. Virginiàna.] 11. =Prùnus Virginiàna=, L. (CHOKE-CHERRY.) Leaves thin, oval-oblong or obovate, abruptly pointed, very sharply, often doubly serrate, with slender teeth. Racemes of flowers and fruit short and close. Fruit dark crimson, stone smooth. Flowers in May; fruit ripe in August; not edible till fully ripe. A tall shrub, sometimes a tree, with grayish bark. River-banks, common especially northward. [Illustration: P. Pàdus.] 12. =Prùnus Pàdus=, L. (SMALL BIRD-CHERRY.) Like Prunus Virginiana, excepting that the racemes are longer and drooping, and the stone is roughened. Occasionally planted for ornament. GENUS =37. PYRUS.= Trees and shrubs, with alternate, stipulate, simple, or pinnately compound leaves. Flowers conspicuous, white to pink, apple-blossom-shaped (5 petals); in spring. Fruit a fleshy pome, with the cells formed by papery or cartilaginous membranes within juicy flesh. * Leaves deeply pinnatifid or fully pinnate (Mountain Ashes) (=A.=) =A.= Leaf deeply pinnatifid, sometimes fully divided at the base. 6. =A.= Leaf once-pinnate throughout. (=B.=) =B.= Leaf-buds pointed, smooth and somewhat glutinous 7. =B.= Leaf-buds more or less hairy 8, 9. * Leaves simple and not pinnatifid. (=C.=) =C.= Leaves entire; fruit solitary (Quinces) 5. =C.= Leaves serrate; fruit clustered. (=D.=) =D.= Fruit large, sunken at both ends (Apples) 1. =D.= Fruit small (½-1 in.), sour, much sunken at the stem end and but little at the other (Crab-apples). (=E.=) =E.= Leaves very narrow; fruit ½ in. 2.