KEY TO THE FAMILIES. 



Petals 2 or 4. 



Stamens 2 or 8 ; fruit indehiscent and 



nut- or bur-like. Onagraceae, 168. 



Stamens 4; fruit a drupe. Cornaceae, 184. 



Petals 5. 



Trees or shrubs; flowers in corymbs. Crataegus, 133. 



Herbs; flowers in umbels or heads. Umbeluferae, 176. 



II. Petals More or Less United into One Piece. 



Stamens more numerous than the corolla-lobes. 

 Ovary 1-celled. 



Ovary with 1 parietal placenta. 

 Ovary with 2 parietal placentae. 

 Ovary 3-many-celled. 



Stamens free from the corolla. 

 Stamens united with the base of the corolla. 

 Stamens as many as the corolla-lobes or fewer. 

 Stamens opposite the corolla-lobes. 

 Stamens alternate with the coroUa-lobes or fewer. 

 Ovary superior. 



Corolla more or less irregular. 

 Fertile stamens 5. 

 Fertile stamens 4 or 2. 



Ovules solitary in the cells of the 

 ovary. 

 Ovary 4-lobed, the style rising 



from between the lobes. 

 Ovary not lobed, the style 

 rising from its apex. 

 Ovules 2 or more, usually nu- 

 merous, in each cell. 

 Ovary and pod 1-celled. 

 Ovary and pod 2-celled. 

 Corolla regular. 



Stamens fewer than the corolla-lobes. 

 Corolla scarious. 

 Corolla not scarious. 

 Style 2-lobed. 

 Style single. 

 Stamens as many as the corolla-lobes. 

 Ovaries 2, separate. 

 Filaments distinct. 

 Filaments monadelphous. 

 Ovary 1. 



Ovary deeply 4-lobed around 

 the style. 

 Leaves alternate. 

 Leaves opposite. 

 Ovary not deeply lobed. 

 Ovary 1-celled. 



Leaves entire, opposite. 

 Leaves, if entire, alter- 

 nate or basal. 

 Corolla conspicuous- 

 ly bearded on the 

 upper surface. 



Leguminosae, 142. 

 Papaveraceae, 112. 



Ericaceae, 188. 

 Malvaceae, 162. 



Primulaceae, 189. 



Verbascum, 220. 



Labi AT AE, 211. 

 Verbenaceae, 211. 



Orobanchaceae, 231. 

 Scrophulariaceae, 219. 



Plantaginaceae, 232. 



Lycopus, 212. 

 Veronica, 225. 



Apocynaceae, 194. 

 asclepiadaceae, 195. 



Boraginaceae, 204. 

 Mentha, 213. 



Gentianaceae, 192. 



Menyanthaceae, 193. 



