(324) 



Ovaries 4, styles 0. U- Jointed aquatics. In- 

 florescence pedunculate; spikes axillary. 



1. P. NATANS L. Floating leaves coria- 

 ceous; submerged leaves filiform. Marine 

 Hospital. Lake Merced. Taylorville. Sum- 

 mer. 



2. P. LUGENS L. Leaves uniform, lanceo- 

 late. Mission Dolores. Lake Merced. Sum- 

 mer. 



3. P. PAUOIFLOBUS Pursh. Leaves linear 

 with distinct stipules. Ocean Lake. Sum- 

 mer. 



4. P. PECTINATUS L. Leaves linear, sti- 

 pules united with the sheathing base of the 

 leaf. Common. Summer. 



ORDER 2. CENTEOSPERM^E. Perigonium 

 0. Ovules basilar. 



Family 1, NAIADACE^l, 



Flowers diclinous. Ovary 1, 1 -celled, 1- 

 ovnlate. Fruit a nutlet. 



1, Lilaea HBK. 



Flowers monoecious. $ , spicate, 1-bracteate, 

 monandrous, sometimes mingled with ? flow- 

 ers. ? flowers partly spicate and 1-bracteate; 

 partly solitary, axillary and without bracts. 

 Styles of the upper ? flowers short, of the 

 lower elongate; stigmas capitate. 0. Aqua- 

 tic. Leaves radical, terete, sheathing at base. 



