320 WATER-PLANTAIN FAMILY. 



8 ALISMA. Flowers perfect, loosely panicled. Petals involute in the tud. 

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

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



i. KCHINODORUS. Flowers perfect, in proliferous umbels. Petals imbricated 

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

 less akenes. 



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

 cessive whorls, the sterile at the summit of the scape; the lowe.'>t fertile. 

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

 receptacle, in fruit becoming flat and winged akenes. 



Iir. FLOWERING-RUSH FAMILY. (Butcher.) Dif- 

 fers from the preceding mainly in the few ovaries having numerous 

 ovules distributed all over the inside. 



e-. LIMNOCHARIS. Flowers perfect, long-pedunoled. Petals large, yellow. Sta- 

 mens numerous with slender filaments, a few of the outei*most without an- 

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

 base. Leaves roundish and heart-shaped, long-petioled. 



1. TRIGLOGHITT, AREOW-GEASS. (Name in Greek means three- 

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

 ter is brackish : fl. summer, y, 



T. paMstre. Slender, 6'- 18' high, with linear-club-shaped ovary and 

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



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

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

 pieces of the fruit sharp-angled on the back. 



T. triindrum, a small slender species along the coast S., has only 3 

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



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

 S. pall^stris. Poat-bogs from Penn. N. . 1° high : fl. early summer. '^ 



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

 meaning.) PI. all late summer. 



A. FlantagO. Shallow water : loaves long-petioled, varying from or oblong- 

 heart-shaped to lanceolate, 3-r5-ribbed; panicle l°-2° long of very many and 

 loose small flowers, y. 



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

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

 hardly so in our species. The following oci'ur in muddy or wet places, chiefly 

 W. & S. : fl. summer ; the flowering shoots or scapes mostly pi-oliferous and 

 creeping. 



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

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



E. rostr^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 ^' wide; 12 stamens; akenes beaked with slender 

 styles, (j) 



E. radlcans, 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 l°-4° long and bearing many whorls ; flowers f-%' broad ; akenes 

 short-beaked. 



5. SAGITTAEIA, AREOW-HEAD. (From the Latin for oirmc, from 

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

 summer, y. 



♦ Filaments lomj and slender, i. e. as long as the lininr-oblong anthers. 

 S. Iancif61ia. Common from "Virginia S. : with the stout leaves l°-.3° 

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



