KEY TO THE GENERA OF TREES 59 



u. Leaves simple, opposite, evergreen, entire, tinder 1 in. long 



73. Buxus. 



u. Leaves simple, deciduous, (v.) 



v. Branches ending in thorns; small trees, or shrubs. (AA.) 

 v. Plants not thorny, (w.) 



w. Leaves palmately lobed (one variety, rarely cultivated, lacks 

 lobes, but is heart-shaped with a serrate margin), the lobes 

 over 3 in number, or with notches or serrations ; fruit dry, 



winged 25. Acer. 



w. Lower leaves palmately 3-lobed, and heart-shaped at base, 

 upper ones ovate, all with entire margin ; fruit with juicy 



pulp covering the 4 seeds 66. Clerodendron. 



w. Leaves palmately lobed ; fruit small, one-seeded, berry-like 

 drupes in large clusters, with flattened stones, or large 

 rounded clusters of flowers without stamens or pistils; 



shrubs rather than trees 47. Viburnum. 



w. Leaves heart-shaped, entire or slightly angulated ; not lobed. 



(DD.) 

 w. Leaves irregularly serrate, somewhat straight-veined ; fruit 



single-winged ; large cultivated tree 60. Fraxinus. 



w. Leaves neither heart-shaped nor lobed ; small trees, almost 



shrubs, (x.) 

 x. Leaves entire, (z.) 



x. Leaves serrate or dentate, ovate or oval, (y.) 

 y. Fruit rounded drupes in large clusters, with single flattened 



stones . . 47. Viburnum. 



y. Fruit lobed pods, which burst open in the autumn ; branch- 

 lets somewhat 4-sided 19. Euonymus. 



z. Leaves small, lanceolate ; flowers and fruit large and beautiful 



42. Punica. 



z. Leaves broad, thin, with curved parallel veins or ribs. 45. Cornus. 

 z. Leaves large, broad, oval, without either curved or straight par- 

 allel ribs 62. Syringa or 63. Chionanthus. 



AA. Leaves entire and covered on both sides with silvery, pel- 

 tate scales 72. Shepherdia. 



AA. Leaves ovate, small, minutely serrate 20. Rhamnus. 



BB. Leaves large, 18 in. or more long; leaflets 11 or more, very 



finely serrated or entire 14. Phellodendron. 



BB. Leaves smaller ; leaflets entire or quite evenly toothed, usu- 

 ally over 5 in number 60. Fraxinus. 



BB. Leaflets coarsely and quite irregularly toothed, 3-5 (rarely 7) 



in number 26. Negundo. 



CO. Leaflets slender-lanceolate ; shrub or small tree with aro- 

 matic leaves and somewhat 4-sided branches 67. Vitex. 



