ALISMACE.E. (WATER-PLANTAIN FAMILY.) 473 



3. ECHINODORUS, Richard. 



Flowers perfect. Sepals 3. Petals 3, imbricated in the bud, withering. 

 Stamens few or numerous. Ovaries few or many, imbricated, forming ribbed 

 acheuia in fruit, usually beaked with the persistent style; Herbs, with peti- 

 oled nerved leaves. Heads mostly bur-like. 



1. E. parvulus, Engelm. Small; leaves lanceolate or spatulate.com- 

 inonly shorter than the 1-6-flowered scape; pedicels mostly clustered, \*e- 

 cnrved iu fruit; stamens 9; acheuia few, obovate, flattened at the sides, and 

 surrounded with 5 prominent ribs, beakless. Margins of shallow ponds, 

 Florida, and westward. July- August. Scapes l'-4' high. Acheuia black 

 and shining. 



2. E. rostratus, Engelm. Leaves ovate, rounded or cordate at the base, 

 5-nerved, about as long as the petiole; scape rigid, longer than the leaves; 

 whorls few ; pedicels erect or spreading ; sepals ovate, shorter than the oval 

 bur-like head; stamens 12; acheuia numerous, strongly 3-ribbed on the back, 

 beaked. South Florida, and westward. Scape simple, 3' -8' high, or occa- 

 sionally 2 high and paniculately branched. Leaves l'-2' long. Flowers 5" 

 wide. 



3. E. radicans, Eugelm. Leaves large, loug-petioled, ovate, cordate or 

 truncate at the base, 7 - 9-ribbed ; scape long, prostrate, rooting, and proliferous ; 

 whorls several, remote ; pedicels spreading or recurved; stamens about 20 ; 

 heads globose ; achenia very numerous, short-beaked, ribbed and slightly den- 

 ticulate on the back. Swamps. July -Sept. Scape 2 -4 long. Leaves 

 3' - 8' long. Flowers 8" - 1 2" wide. 



4. SAGITTARIA, L. ARROW-GRASS. 



Flowers monoecious, racemose, the upper ones sterile. Sepals 3, persistent. 

 Petals 3, imbricated in the bud, withering. Stamens few or many. Ovaries 

 crowded in a globular head. Achenia flat, membranaceous, winged. Marsh 

 or aquatic herbs, with scape-like stems, and variouslv shaped nerved and 

 reticulated sheathing leaves, which are often without a blade. Flowers white, 

 commonly three in a whorl from the axils of persistent bracts. 



* Filaments long and slender. 



1. S. lancifolia, L. Tall; leaves erect, rigid, from broadly to linear 

 lanceolate, acute at each end, pinnately nerved, on long and stout petioles ; 

 scape longer than the leaves, often branching above; pedicels of the sterile 

 flowers slender, longer than those of the fertile ones ; bracts and sepals ovate, 

 obtuse, granular-roughened ; stamens numerous, with hairy filaments ; acheuia 

 obliquely obovate, wing-keeled, strongly beaked. Lakes and rivers, Florida 

 to South Carolina, and westward. June - Sept. Scape 2 - 5 high. Leaves 

 1- 2 long. Flowers 1'- 1^' wide. 



2. S. variabilis, Engelm. Leaves mostly sagittate, acute or obtuse, 

 varying from linear to broadly ovate, smooth, or rarely, like the scape, bracts, 

 and sepals, pubescent ; bracts acute ; flowers mostly large ; pedicels of the 



