Pondweed Family 13 



1. N. flexilis (Willd.) E. & S. Stem slender, forking; leaves 

 linear pellucid, acuminate or acute, 1-2 cm. long, 1-2 mm. wide, 

 numerous and crowded on the upper branches with 25-30 minute 

 teeth on each margin ; fruit 2-4 mm. long, 0.5-1 mm. in diameter ; 

 style long, persistent; stigmas short. 



Near Soldiers' Home, Hasse, Davidson. 



4. ZOSTER A L. EEL-GRASS. 



Marine plants, wholly submerged, with slender root- 

 stocks and branching compressed stems. Leaves 

 2-ranked, sheathing at the base, the sheaths with in- 

 flexed margins. Spadix linear, contained in a spathe. 

 Flowers monoecious, arranged alternately in 2 rows on 

 the spadix. Staminate flower merely an anther attached 

 to the spadix near its apex, 1-celled ; pollen thread-like. 

 Pistillate flower fixed on its back near the middle. 

 Ovary 1 ; style elongated ; stigmas capillary. Mature 

 carpels flask-shaped, beaked by the persistent style. 

 Seeds ribbed ; embryo ellipsoidal. 



1. Z. marina L. Leaves ribbon-like, obtuse at the apex, 0.5-2 

 m. long, 5-10 mm. wide; spadix 2-5 cm. long; flowers about 6 

 mm. long, crowded. 



Shoal waters in bays on muddy bottoms. San Pedro. 



5. PHYLLOSPADIX HOOK. 



Submerged marine plants with thickened rootstocks 

 and slender stems, which bear the inflorescence at the 

 summit or in clusters along the upper part. Leaves 

 linear, sheathing. Flowers dioecious in spathes like 

 those of Zostera. Spathes with membranous edges, the 

 back thickened and terminating in long leaf-like ap- 

 pendages. Spadix with a series of short dilated foli- 

 aceous flaps, which close over the flower, spreading open 

 at maturity. Staminate flowers of numerous sessile 

 stamens in 2 rows ; anthers 1-celled. Pistillate of sim- 

 ple sessile ovaries, attenuate into a short style ; stigmas 



