320 WATER-PLANTAIN FAMILY. 



3. ALISMA. Flowers perfect, loosely panioled. Petals involute in the bud. 



Stamens 6. Ovaries many, in a ring, very flat-sided, becoming coriaceous 

 flat akenes, 2 - 3-keeled on the back. 



4. KCHINODOKUS. Flowers perfect, in proliferous umbels. PetaJs imbricated 



in the bud. Stamens 9 or more. Ovaries heaped iu a head, becoming wing- 

 less akenes. 

 6. SAGITTARIA. Flowers monoecious, rarely dioecious or polygamous, in suc- 

 cessive whorls, tiie sterile at the summit of the scape ; the lowest fertile. 

 Stamens usually numerous. Ovaries very many, heaped on the globular 

 receptacle, in fruit becoming flat and winged akenes. 



III. FLOWERING-RUSH FAMILY. (Buto.be^.) Dif- 

 fers from the preceding mainly in the few ovaries having numerous 

 lovules distributed all over the inside. 



6- LIMNOCHAEIS. Flowers perfect, long-peduncled. Petals large, yellow. Sta. 

 mens numerous with slender filaments, a few of the outermost without an- 

 thers, the rest with linear anthers. Ovaries 6 or more, somewhat united at 

 base. Leaves roundish and heai-t-shaped, long-petioled. 



1. TEIGLOCHIM", AEROW-GKASS. (Name in Greek means three- 

 pointed. ) Insignificant rush-like plants, in marshes, mostly where the war 

 ter is brackish : fl. summer. ^ 



T. pall!L3txe. Slender, 6' -18' high, with linear-club-shaped ovary and 

 fruit, the 3 pieces when ripe .separating from the sharp-pointed base upwards. ., 



T. maritiinuin. Stouter, 12' -20' high, with fruit of about 6 pieces 

 rounded at base. — Var. elA.tum, in bogs of the interior, N., 20' -30' high, the 

 pieces of the fruit sharp-angled on the back. 



T. trid-ndrum, a small slender species along the coast S., has only 3 

 sepals, no petals, 3 stamens, and a 3-lobed fruit 



2. SGHEUCHZEKIA. (Named for the early Swiss botanist, Scheuchzer. ) 

 S. paltistris. Pea^bogs from Penn. N. : 1° high : fl. early summer. ^^ 



3. ALISMA, "WATER-PLANTAIN. (The old Greek name, of uncertain 

 meaning. ) Fl. all late summer. 



A. Flant^gO. Shallow water : leaves long-petiolcd, varying from or oblong- 

 heart-shaped to lanceolate, 3-5-ribbed ; panicle l°-2° long of very manj' and 

 loose small flowers. ^ 



4. ECHIN6D0RUS. (Named probably from Greek words for prickli/ 

 flask, the head of fruit being as it were prickly-pointed by the styles, but 

 hardly so in our species. The following occur in muddy or wet places, chiefly * 

 W. & S. : fl. summer ; the flowering snoots or scapes mostly proliferous and 

 creeping. 



E. p^rvulus : a tiny plant, l'-3' high, with lanceolate or spatulate leaves, 

 few-flowered umbels, 9 stamens, and almost pointless akenes. ® 



£. rostrd.tus, with broadly heart-shaped leaves (l'-3' long, not including 

 the petiole) shorter than the erect scape, which bears a panicle of proliferous 

 umbels ; flower almost J' wide ; 12 stamens ; akenes beaked with slender 

 styles. ® 



E. radicaus, with broadly heart-shaped and larger leaves (3' - 8' wide) 

 which are Very open or almost truncate at base ; the creeping scapes or stems 

 becoming 1° -4° long and bearing many whorls ; flowers ^'-1' broad ; akenes 

 short-beaked. 



5. SAGITTAHIA, ARROW-HEAD. (From the Latin for aiTow, from 

 the sagittate leaves which prevail in the genifs. In shallow water : fl. all 

 summer, y, 



» Filaments long and slender, i. e. as long as the linear-oblong anthers. 

 S. lancifblia. Common from Virginia S. : with the stout leaves l°-3° 

 and scapes 2° - 5° high, the coriaceous blade of the former lance-oblong and 



