(71) 



2. Corallorhiza. Labellum not geniculate, 

 adnate to the column. Aphyllous and 

 and without chlorophyll. 



3. Spiranthes. Labellum not geniculate, 

 embracing the column with its base. 

 Perigonium oblique. 



II, Diandria, 



1. Cypripedium. 



III. Hexandria. 



1. Aristolochia. 



MONffiCIA, 



I, Monandria, 



1. Euphorbia. Involucre campanulate, 

 sometimes 2-phyllous. Flowers umbel- 

 late, androgynous. $ flowers without 

 perigonium, stipitate, bracteate, 9 flow- 

 ers single, central. Ovary 3-celled, styles 

 3, each 2-cleft. 



2. Zostera. Spathe elongated into a lamina. 



Spadix androgynous. Ovary 1-celled, 

 1-ovulate. Fruit a nutlet. Aquatic. 



3. Lilsea. Flowers spicate. $ , $ , and 

 androgynous spikes present, besides 

 solitary axillary ? flowers. Aquatic. 



4 Najas. Flowers axillary, solitary. $ 

 flowers included in a spathe : $ flowers 

 naked. Ovary 1, 1-ovulate. Fruit 

 drupaceous. Aquatic. 



