KEY TO FAMILIES 



Petals present 



1. Flowers in heads, as in the aster and clover 



a. Ovary superior Trifolium in 



Fabaceae 186 



b. Ovary inferior 



(1) Petals separate; style simple; upper leaves 



in a whorl of 4-6 Cornaceae 222 



(2) Petals united; style 2-cleft ; leaves rarely 



whorled 

 2. Flowers single or in clusters 

 a. Petals separate 

 (1) Petals 1-3 



(a) Petal 1 ; stamens 10; shrub 



(b) Petals 2 



x. Ovary superior, smooth 



(x) Water plants; stamens 2-3 

 (v) Land plants; stamen 1 



y. Ovary inferior, bristly-hairy 



Asteraceae 243 



Amorpha ix Faba- 

 ceae 170 



Elatinaceae 42 



Calyptridium in 



Portulacaceae 

 49 



ClRCAEA IN ONA- 

 GRACEAE 201 



(c) Petals 3 

 x. Sepals green, unlike the petals 



(x) Leaves grass-like; flower withering 



in a few hours Commelinaceae 



304 

 (y) Leaves usually broad; flower per- 

 sistent 

 m. Pistils 6-many, distinct ; water 



plants Alismaceae 299 



n. Pistil 1, compound, with 3 cells; 



land plants • Liliaceae 304 



y. Sepals and petals more or less alike in 

 color 

 (x) Flowers regular 



