92 



ZAXXICHELLIACEAE 



1. Zannichellia palustris L. 



Horned Pondweed. Fig. 194. 



Zannichellia palustris L. Sp. PI. 969. 1753. 



Stems capillary, sparsely branched, from 

 creeping rhizomes. Leaves all submerged, 

 capillary, 2-10 cm. long, acute or almost pun- 

 gent at the apex, 1-nerved ; stipules scarious, 

 free from the leaf-bases, scarcely 2 cm. long ; 

 staminate and pistillate flowers in the same 

 leaf-axil, subtended or inclosed by a hyaline 

 bract; staminate flower of a solitary 2-celled 

 anther on a slender filament ; pistillate flowers 

 of 2-10 carpels, sessile at first, often pediceled 

 after antliesis ; carpels flask-shaped, ribbed or 

 toothed on the margins, or sometimes smooth ; 

 style recurved, persistent ; stigma cup-shaped, 

 with dentate or angled edges ; mature fruit 

 2^ mm. long, rarely pitted. 



In fresh or brackish water, nearly cosmopolitan in 

 its distribution. Type locality: Europe. 



v. vy r / 



Family 5. NAIADACEAE. 

 Naias Family. 



Slender, branching, submerged aquatics from fibrous roots. Leaves all sub- 

 merged, opposite or whorled, spiny-toothed, sheathing at the base. Flowers 

 monoecious or dioecious, axillary, solitary, sessile or pediceled. Staminate with 

 a double perianth ; the outer entire or 4-toothed at the apex, the inner one hyaline, 

 adhering to the anthers. Stamen 1, sessile or stalked; anthers 1-4-celled, apicu- 

 late or 2-lobed at the summit. Pistillate flowers of a single ovary, tapering into 

 a short style ; stigmas 2-4, subulate. Fruit a solitary carpel, sessile, ellipsoidal, 

 with a crustaceous pericarp. 



a family with only the following genus. 



1. NAIAS. L. Sp. PI. 1015. 1753. 



Slender branching submerged aquatics, with the characters of the family. [Greek, water- 

 nymph.] 



A genus of about 10 species living in fresh water, and widely distributed over the vv'orld. Type species, 

 Naias marina L. 



Flowers dioecious; internodes and back of leaf spiny. 

 Flowers monoecious; internodes and back of leaf unarmed. 



Anthers 1-celled; seeds shining, appearing smooth. 



Anthers 4-celled; seeds dull, reticulate. 



1. Naias marina L. Large Naias. 



Naias marina L. Sp. PL 1015. 1753. 



Naias major All. Fl. Ped. 2: 221. 1785. 



Naias marina calif arnica Rendle, Trans. Linn. Soc. 11. 5: 398. 

 1889. 



Stems branched, sometimes dichotomously, armed 

 with brownish spinulose teeth on the internodes. 

 Leaves opposite or alternate, stiff or recurved, nar- 

 rowly linear, 1-4.5 cin. long, 0.5-3 mm. wide, with 

 toothed margins, and often dorsally toothed on the 

 midrib, the teeth triangular, apiculate. 1 mm. or more 

 long; leaf-bases sheathing, the sheaths rounded, with- 

 out teeth or rarely with a few short teeth ; flowers 

 dioecious, the staminate 3-4 mm. long ; anther 4- 

 celled ; pistillate flower usually 3-4 mm. long; stigmas 

 3, sometimes one shorter than the others ; mature 

 fruit apparently tessellated in dried specimens, smooth 

 when fresh. 



Growing in quiet fresh water and widely distributed over 

 the world. On the Pacific Coast ranging from Clear Lake, 

 California, to Lower California, but not common. Type 

 locality: Euro;ie. 



1. N. marina. 



2. A^. flexilis. 



3. A'', guadalupensis. 



Fig. 195. 



