320 WATER-PLANTAIN FAMILY. 



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



Stamens 6. Ovaries many, in a ring, very flat-sided, becoming coi'iaceous 

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



4. P:CHIN0I)0KUS. Flowers perfect, in proliferous umbels. Petals imbricated 



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

 less akenes. 



5. SAGITTARIA. Flowers monoecious, rarely dicecious or polygamous, in suc- 



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

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

 receptacle, in fruit becoming flat and winged akenes. 



III. FLOWERING-RUSH FAMILY. (Butojie^.) Dif- 

 fers i'rom the preceding mainly in the few ovaries having numerous 

 ovules distributed all over the inside. 



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



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

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

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



1. TRIGLOCHIN, ARROW-GRASS. (Name in Greek means three- 

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

 ter is brackish : fl. summer. 21 



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

 fruit, 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. elXtum, in bogs of the interior, N., 20' -30' high, the 

 pieces of the fniit sharp-angled on the back. 



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

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



2. SCHEUCHZERIA. (Namedfor the early Swiss botanist, AScAewc/izfir.) 

 S. pallistris. Peat-bogs from Penn. N. : 1° high : fl. early summer, y. 



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

 meaning.) Fl. all late summer. 



A. Plant^gO. Shallow water : leaves long-petioled, varying from or oblong- 

 heart-shaped to lanceolate, 5-5-i'ibbed ; panicle l°-2° long of very many and 

 loose small flowers. 21 



4. ECHINODdRUS. (Named probably from Greek words for prickly 

 flush, the head of fruit being as it Avere prickly-pointed by the styles, but 

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

 AV. & S. : fl. summer ; the flowering shoots or scapes mostly proliferous and 

 creeping. 



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

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



E. rostratUS, with broadly heart-shaped leaves (l'-3' long, not including 

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

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

 styles. (T) 



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

 which arc very open or almost truncate at base ; the creeping scapes or stems 

 becoming l°-4° long and bearing many whorls ; flowers j -%' broad ; akenes 

 short-beaked. 



5. SAGITTARIA, ARROW-HEAD. (From the Latin for arroiv, from 

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

 summer. 2/ 



* Filaments lonq and slender, i. e. as lonq ns the linear-ohlong anthers. 

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

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



