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1. L. SUBULATA HBK. — San Francisco. 

 School House Station. Searsville. Spring. 



2. Zostera L. Eel-Grass. 



Flowers monoecious. Spatlie elongated into 

 a lamina. Spadix flattened, dorsally naked, 

 ventrally covered by alternate stamens and 

 ovaries arranged in two rows. Anthers 1-celled, 

 sessile. Ovary rostrate. Style persistent. — 

 U . Stems and roots submerged. 



1. Z. MARINA L. — Brackish inlets around the 

 bay. Summer. 



The bulbous root is edible, and is eagerly 

 sought for by the canvas-back duck. 



Family 2. LEMNACEiE. 



Aquatic plants without axis. Flowers en- 

 closed in a thin membranaceous spathe. Sta- 

 mens 1 or 2. Ovary sessile, i-celled; ovules 

 1-6; style short. Fruit a utricle. 



1. Lemna L- Duckweed. 



Stamens 2. 



1. L. TRISULCA L. Ovule solitary; fronds 

 oblong, stalked, remaining connected. — Presi- 

 dio. Autumn. 



2. L. Valdiviana Philippi. Ovule solitary; 

 fronds not stalked, soon separating; bract reni- 

 form. — Marine Hospital. Autumn. 



