ALISMACE^. (water-plantain FAMILY.) 473 



3. ECHINODORUS, Richard. 



Flowers perfect. Sepals 3. Petals 3, imbricated in the hud, witliering. 

 Stanieus few or uumerous. Ovaries few or mauy, imbricated, furmiug ribbed 

 achenia in fruit, usually beaked with the persistent style. — Herbs, with peti- 

 oled nerved leaves. Heads mostly bur-like. 



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

 monly shorter than the I-6-tlowered scape; pedicels mostly clustered, i*e- 

 curved in fruit; stamens 9; achenia few, obovate, flatteued at the sitles, and 

 surrounded with 5 prominent ribs, beakless. — Margins of sliallow jjonds, 

 Florida, and westward. July- August. — Scapes T- 4' high. Achenia black 

 and sliiuing. 



2. E. rostratus, P'ngelm. Leaves ovate, rounded or con hate at tiie base, 

 5-nervetl, about as long as the petiole; scape rigid, longer tiiau the leaves; 

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

 bur-like head; stamens 12; achenia 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 I' -2' long. Flowers 5" 

 wide. 



3. E. radieans, Engelm. Leaves large, long-petioled, ovate, cordate or 

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

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

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

 ticulate ou the back. — Swamps. July -Sept. — Scape 2°-4° loug. Leaves 

 3' -8' long. F^lowers 8"- 12" wide. 



4. SAGITTARIA, L. Arrow-grass. 



Flowers monoecious, racemose, tlie 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 variously shajied nerved and 

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

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



* Filaments loiuj 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 tlie fertile ones; bracts and sepals ovate, 

 obtu.se, granular-roughened ; stamens numerous, with hairy filaments ; achenia 

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

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

 l°- 2° long. Flowers 1'- 1^' wide. 



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

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

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



