46 % KEYS TO THE GENERA 



A. Flowers inconspicuous, usually greenish. l\hamnus (p. 0:]). 

 Zfzyphus (p. 00). 



A. Leaves thick and about evergreen. B^rberis (p. G4). Pyracaiitha 

 (p. 175). ilex (p. 8G). 



* Plants not spiny. (B.) 



B. Leaves straight-veined but not oblique at base. (C.) 



C. Fruit cone-like and hanging on till fall or through the year. 



Alnus (p. 312). Betula (p. 311). 

 C. Fruit round nuts i-^ inch, ripe in fall. Corylus (p. 313). 



Castknea (p. 314). Qudrcus (p. 314). 

 C. Fruit not as above, in some cases absent. (D.) 

 D. Flowers white of many long stamens in snowy wreath. 



Neviusia (p. 171). 

 D. Flowers white, sweet-scented, with 5 petals in erect clusters 

 in summer. Cl^thra (p. 205). 

 B. Leaves with oblique base. (E. ) 

 E. Straight-veined. Ulmus (p. 308). Hamam^lis (p. 202). 

 Fothergilla (p. 203). Coryl6psis (p. 204). 



E. Three-ribbed from base, small, 1 inch long. Zizyphus (p. 00). 

 B. Leaves heart-shaped at base. (F.) 



F. With curved parallel side ribs. Ehamnus cathartica (p. 00). 

 F. No such parallel ribs. (G.) 



G. Fruit cone-like, under 1 inch long, hanging on through the 



year. Alnus (p. 312). 

 G. Fruit round nuts, ripe in the fall. C6rylus (p. 313). Casta- 



nea (p. 314). 

 G. Fruit dry capsule, 2-celled, 2-seeded. Coryldpsis (p. 204). 

 Fothergilla (p. 203). 

 B. Leaves not as above. (H.) 

 H. Leaves deciduous and (I.) 



I. Very narrow linear or nearly so. Salix (p. 314). Itea 



(p. 201). Ehamnus (p. 93). 

 I. Tliree- or more ribbed from base. (J. ) 

 J. Flowers with petals more or less united at base. (K. ) 

 K. Flowers large, 1 inch or more, funnel-shaped (sometimes 



double). Azalea (p. 257). 

 K. Flowers bell-shaped (^-1 inch). Styrax (p. 270). Ha- 



l^sia (p. 272). 

 K. Flowers tubular, globular, or urn-shaped (^ inch or 

 less). (L.) 

 L. Fruit a capsule. Andromeda (p. 240). 

 L. Fruit berry-like with 10 or more seeds. Gaylussacia 

 and Vaccinium (p. 244). 



