68 Spring Flora of Ohio. 



17. Genus PRU'-NUS. — ^ Calyx o-cleft, petals 5, spreading; stamens 

 15-20, pistil solitary; drupe fleshy with a bony stone; trees or shrubs. 

 Besides the species named below, this genus also includes the culti- 

 vated Plums, Cherries, Peach, Apricot, etc. 



A. Fknuers with or preceding the leaz'es in 7imhel-like clusters. 



Pru'-nus a-mer-i-ca'-na Marsh. Wild Yellow or Red Plum. — Tree 



thorny, 8-'20 ft. high; leaves conspicuously pointed, coarsely and 

 doubly serrate, very veiny; fruit Yz-^i in. in diameter. 



Pru'-nus penn-sy!-van'-i-ca L,. f. Wild Red Cherry. — Tree 20-30 ft. 

 high; leaves pointed, finely and sharply serrate, shining green and 

 smooth both sides ; fruit light red, very small, sour. 



A. Flo7vers in racemes, appearing after the leaves. 



Pru'-nus vir-gin-i-a'-na L,. Choke Cherry. — A tall shrub or occasionally 

 a tree ; leaves oval, oblong or obovate, abruptly pointed, very sharply, 

 often doubly serrate with slender teeth, thin ; petals roundish. 



Pru'-nus se-rot'-i-na Ehrh. Wild Black Cherry. — A large tree ; leaves 

 oblong or lanceolate-oblong, taper-pointed, serrate with incurved short 

 and callous teeth, thickish, shining above; petals obovate. 



XXXVII. Order LE-GU-IHIN-O'-S/E. PEA FAMILY.— Flowers mostly 



papilionaceous, or sometimes regular; stamens 10 (rarely 5 or many), 

 distinct or united by their filaments ; pistil simple, free ; fruit a legume. 



Trees or shrubs (a). 



Herbs (c). 

 a. Leaves compound (b). 

 a. Leaves simple, round-cordate ; flowers preceding the leaves Cercis. 1 



b. Trees thorny , leaves 1-2-pinnate, leaflets small ; calyx short, 3 



to 5-cleft ; flowers not papilionaceous Gleditschia. 2 



b. Trees not thorny ; leaves all doubly pinnate, very large ; cah'x 

 elongated-tubular below, 5-cleft ; flowers not papilionace- 

 ous Gyninocladiis. 3 



b. Trees and shrubs, leaves pinnate; flowers papilionaceous f;. 



c. .Stamens (lO) distinct, pod inflated Baptisia. 4 



c. Stamens monadelphous or diadelphous (9 & 1) (d). 



d. Leaves palmate (digitate), leaflets 7-11 Lupinus. 5 



d. Leaves trifoliate ie). 



d. Leaves abruptly pinnate (g). 



e. Flowers racemed or spiked, pods curved or coiled Medicago. 6 



e. Flowers racemed, pods coriaceous, wrinkled Melilotus. 7 



€. Flowers in heads, pods membranaceous Trifolium. 8 



f. Woody twiner, pod thickish Kraunhia. 9 



f. Trees or shrubs, pod flat Robinia. 10 



g. Leaves terminated by a bristle or tendril. Vicia. 11 



