KEY TO FAMILIES . xxvii 



(m) Petals very hairy on the upper 



face Menyanthaceae 



99 

 (n) Petals smooth 

 r. Flowers regular; terrestrial Hydrophvllaceae 



116 

 s. Flowers irregular; aquatic Pixguiculaceae 139 

 (y) Carpels 5 Primulaceae 88 



y. Ovary 2-celled, 2-divided or 4-lobed 

 (x) Ovary 2-celled or 2-divided 

 m. Leafless herbs ; plants not green 

 (m) Stems twining; flowers regu- 

 lar Cuscutaceae 109 

 (n) Stems not twining; flowers ir- 

 regular Orobanchaceae 140 

 n. Leafy herbs 

 (m) Stamens 5 

 r. Ovary 2-lobed or pistils 2 and 

 separate 

 (r) Stamens distinct, around a 



crown Asclepiadaceae 101 



(s) Stamens united; crown 



none Apocynaceae 100 



s. Ovary 1, 2-celled, not 2-lobed 

 (r) Seeds 2-several ; mostly 



climbing or trailing Convolvulaceae 



108 

 (s) Seeds many Solanaceae 110 



(n) Stamens 4 



r. Corolla brightly colored, the 

 lobes usually 5 

 (r) Fruit a 2-celled capsule Scrophulariaceae 



125 

 (s) Fruit 2 or 4 1-seeded nut- 

 lets Yerbexaceae 142 

 s. Corolla papery, the lobes 4 Plantaginaceae 92 

 (y) Ovary 4-lobed or divided 

 m. Flowers usually irregular; leave? 



opposite Lamiaceae 143 



