20 KEY TO THE FAMILIES 



Flowers not involucrate ; leaves alternate. 

 Bracts none ; flowers greenish . . . Chenopodiaceae, 83 

 Bracts and flowers thin and dry, not green.. 



Amaranthaceae, 83 



Bracts leaf-like, densely hairy Eremocarpus, 150 



Calyx adherent to the ovary. (Ovary inferior.) 

 Leaves entire; flowers perfect. 



Aquatic ; leaves densely whorled Haloragidaceae, 169 



Land plants; leaves alternate or basal. 



Seeds many; leaves broad-heart-shaped 



Aristolochiaceae, 75 



Seed solitary ; leaves elliptic Santalaceae, 74 



Leaves deeply toothed or lobed; flowers lacking sta- 

 mens or pistils. 



Erect herb; seeds numerous, small Datiscaceae, 162 



Climbing herb; seeds several, large Cucurbitaceae, 237 



II. CHORIPETALOUS SECTION. Calyx and 

 corolla both present, the latter of distinct petals. 

 (III. on p. 22.) 



A. Stamens more than double the number of petals 

 (always more than 10). (B. on p. 21.) 



Stamens free from the calyx (hypogynous). 



Pistils few to many, distinct Ranunculaceae, 94 



Pistil 1, compound. 



Sepals falling as the corolla opens Papaveraceae, 101 



Sepals persistent; aquatics with broad floating 



leaves Nymphaeaceae, 93 



Sepals persistent; land plants. 

 Petals more numerous than the sepals (5 to 16) ; 



succulent plants Portulacaceae, 84 



Petals of the same number as the sepals (5). 

 Leaves alternate ; flowers not yellow ; stamens 



all united Malvaceae, 157 



Leaves opposite, entire; flowers yellow; sta- 

 mens united into bundles Guttiferae, 159 



Stamens borne on the calyx (perigynous). 

 Leaves opposite, simple. 



Petals 4, white Philadelphus, 121 



Petals many, red Calycanthaceae, 101 



Leaves alternate, with stipules; flowers white yellow 



or pinkish Rosaceae, 123 



Leaves alternate, without stipules, rough; flowers 



yellow Loasaceae, 161 



