(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. J*. LUCENS L. Leaves uniform, lanceo- 

 late. — Mission Dolores. Lake Merced. Sum- 

 mer. 



3. P. PAUOIFLORUS Pursh. Leaves linear 

 with distinct stipules. — Ocean Lake. Sum- 

 mer. 



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

 pules united with the sheathing base of the 

 leaf. — Common. Summer. 



Order 2. CENTKOSPEEMiE. Perigonium 

 0. Ovules basilar. 



Family 1. NAIADACE^. 



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

 ovulate. Fruit a nutlet. 



1. Lilaea HBK. 



Flowers monoecious. S , 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. 



