A KEY TO THE FAMILIES. 



PAGE 



A.. Parts of the flower nearly always in threes; 

 leaves almost always parallel-veined. 



a. Ovary superior. 



b. Leaves often arrow-shaped; pistils many, in a head. 



Alismaceae 2 



b. Leaves not arrow-shaped; pistil one. Liliaceac 4 

 a. Ovary inferior. 



b. Flowers regular; stamens three. Iridaceae 66 



b. Flowers irregular; stamens one or two. Orchidaceae 72 



A. Parts of the flower mostly in fours or fives; 



leaves mostly netted-veined. 

 B. Corolla absent; calyx mostly present, some- 

 times showy. 



a. Ovary superior. 



b. Pistils several to many, distinct. Ranunculaceae 126 

 b. Pistil one, one to several-celled. 



c. Flowers in long spikes with a white involucre 



at base. Saururaccae 80 



c. Flowers not in long spikes. 



d. Stipules if present sheathing the stem; 



sepals three to six. Polygonaceae 86 



d. Stipules absent; sepals mostly five. 



Chenopodiaceae 96 

 a. Ovary inferior or appearing so by the closely fitting 



calyx. 

 b. Ovary six-celled; stamens six to twelve. 



Aristolochiaceae 84 



b. Ovary one-celled; stamens three to five. 

 c. Leaves opposite; flowers often showy. 



Nyctaginaceae 100 

 c. Leaves alternate; flowers not showy. 



Santalaceae 8a 



B. Both corolla and calyx present. 

 C. Corolla of separate petals. 

 D. Ovary superior. 



a. Stamens more than ten in number. 



b. Pistils several to many, separate or 



united below. 

 c. Pistils separate and distinct. 



d. Pistils enclosed in a hollow recep- 

 tacle. 



e. Leaves opposite; petals num- 

 erous. Calycanthaceae 158 

 e. Leaves alternate ; petals most- 

 ly five. Rosaceae 218 

 d. Pistils not enclosed in a recep- 

 tacle, 

 e. Stamens attached to the 



calyx. Rosaceae 218 



e Stamens not attached to the 



calyx. Ranunculaceae 126 



XV 



