100 KANSAS ACADEMY OF SCIENCE. 



KEY TO THE GENERA. 

 Lvs. deciduous, trees not cone-bearing (1). 

 Lvs. evergreen, needle-shaped or scale-like (47). 



1. Lvs. simple (2). 



1. Lvs. compound (36). 



2. Lvs. alternate (3). 

 2. Lvs. opposite, or verticillate (.34). 

 3. Lvs. entire (4). 



3. Lvs. serrate, dentate, cut-toothed or lobed (9). 

 4. Branches more or less spiny or thorny (5). 

 4. Branches free from spines or thorns (6). 



5. Lvs. nearly smooth, wedge-oblong, or oval-lanceolate; fr. cherry-like 21 (Bumelia.) 



■5. Lvs. shining above, strongly veined beneath, ovate or ovate-oblong, fr. orange- 

 like 29 (Madura.) 



6. Lvs. broadly-ovate-cordate, 3'-4' long, 4'-5' wide 16 (Cercis.) 



6. Lvs. not as above (7). 



7. Lvs. obovate-lanceolate, 6'-12' long, pointed; fr. 3'-4' long 1 (Asimina.) 



7. Lvs. lanceolate-oblong, shining above, downy beneath; fr. an acoru 3S (Quercus.) 



7. Lvs. ovate or ovate-oblong; fr. globular, y-V in diameter (8). 



8. Lvs. ovate, bark spicy, aromatic; twigs and foliage mucilaginous 25 (Sassafras.) 



8. Lvs. ovate oblong, thickish, bark astringent; fr. edible when ripe 22 (Diospyros.) 



9. Trunk or branches armed with thorns or spines (10). 

 9. Trunk and branches unarmed (14). 



10. Lvs. very obscurely denticulate; fr. large, orange-like 29 (Madura.) 



10. Lvs. plainly serrate, cut or toothed ; fr. small or medium (11). 

 11. Lvs. finely serrulate, or serrate above the middle (12). 

 11. Lvs. coarsely or sharply serrate, cut or toothed (13). 



12. Lvs. obovate and oblauceolate, serrate above the middle; thorns 2'-3' 



long 19 (Crataegus.) 



12. Lvs. nearly lanceolate, finely serrulate, thorns not prominent 17 (Prunus.) 



13. Lvs. coarsely or doubly serrate, conspicuously pointed, ovate 17 (Prunus.) 



13. Lvs. sharply cut or toothed, roundish-ovate, ovate-oblong or obovate 19 (Crat;egus.) 



14. Bark white, detached (at least on the branches) annually in thin plates, 



lvs. broad, palmately lobed 30 (Platanus.) 



14. Bark, Ac, not as above ( 15). 



15. Trees small, sometimes only shrubs (It!). 



15. Trees large, bark more or less furrowed or laminated (23). 



16. Lvs. large, sometimes 3-lobed; twigs yellowish green, bark spicy 25 (Sassafras.) 



16. Lvs. &c., not as above ( 17). 



17. Lvs. mostly narrow elongated, leaf-like stipules deciduous, fr. a 1-celled pod 37 (Salix.) 



17. Lvs. and fr. not as above ( 18). 



15. Lvs. obtusely or obscurely serrate or crenate-serrate ( 19.) 

 18. Lvs. sharply serrate, cut or toothed (20.) 



lit. Lvs. oblong-oval, parallel veins prominent, fr. purple, berry-like 7 (Rhamnus.) 



19. Lvs. obovate, downy on the midrib beneath, fr. a red, berry-like drupe 5 (Ilex.) 



19. Lvs. oblong or lanceolate, scarcely veiny, fr. greenish, acerb IS (Pyrus.) 



20. Lvs. downy or somewhat pubescent; straight-veined, fr. a nut or hop- 

 like (21.) 



20. Lvs. glabrous, at least when mature; fr. an apple, or berry-like (22). 



21. Bark brownish furrowed; fr. hop-like in appearance 34 (Ostrya.) 



21. Bark close, smooth, gray; fr. a nut with halberd-shaped bracts 35 (Carpinus.) 



22. Fr. purplish, sweet, ripe in June; lvs. oblong-ovate, 2'-3' long, acumi- 

 nate 20 (.\melanchier.) 



22. Fr. greenish, acerb; lvs. ovate or lanceolate 18 (Pyrus.) 



23. Lvs. broadly sub-cordate, often truncate at base or deltoid (24). 

 23. Lvs. not as above (25). 



24. Lvs. serrate with incurved teeth; buds covered with varnish 3"* (Populus.) 



24. Teeth not incurved, inner bark easily peeled otl'; buds unvarnished 2 (Tilia.) 



25. Lvs. linear, lanceolate or ovate-lanceolate, stipules often conspicuous 37 (Salix.) 



25. Lvs. varying ; not as above (26). 

 26. Lvs. lobed (27;. 

 26. Lvs. serrate (28). 



27. Fr. an acorn, bark with much tannin 3.3 ((iuercus.) 



27. l''r. a drupe ; twigs yellowish-green, bark spicy aromatic 25 (Sassafras.) 



27. Fr. blackberry-like; lvs. rough above, lobed only on young shoots 28 (Morus.) 



