556 ALISMACE^E. ( WATER- PL ANT A IN FAMILY.) 



crested. (S. pusilla, Pursh.) In mud or shallow water, near the coast; 

 N. Y. to Fla. 



Var. (?) gracillima, Watson. Scape and the almost or wholly bladeless 

 leaves very slender and greatly elongated (2-4 long, 1" wide) ; pedicels all 

 elongated, in usually distant whorls, the lower pistillate, slender and spread- 

 ing ; fruit unknown. ( S. natans, Engelm. in Torr. Bull. ix. 4.) In deep water 

 of streams in E. Mass. (Hitchings, Boott, C. E. Faxon, etc.) Wholly sub- 

 merged, only 1 or 2 flowers appearing at a time, floating on the surface. The 

 fruit, maturing under water, has not yet been collected. 



2. LOPHIOCABPUS. Fertile flowers perfect; stamens 9-15, at the base 

 of the receptacle; sepals erect and embracing the fruit. 



7. S. calycina, Engelm. Scape weak (3 - 9' high), at length mostly pro- 

 cumbent ; usually only the lowest whorl fertile, with pedicels as long as those 

 of the sterile flowers, recurved in fruit ; bracts orbicular, obtuse or rarely pointed ; 

 filaments slighUy rough, as long as the anthers ; achenes obovate with a short 

 horizontal style ; leaves broadly halberd-shaped, obtuse or acutish, with wide 

 spreading lobes, often wider than long, or lanceolate or sometimes reduced to 

 linear phyllodia. Maine to Del., west to Wise., Mo., and Tex. Quite vari- 

 able, several forms being enumerated, as var. sroNGi6sA, with spongy texture 

 and bladeless submerged leaves, eastward ; and westward, var. FLtiiTAxs, with 

 lance-linear floating leaves. 



3. ECHIN6DORUS, Richard. 



Flowers perfect. Petals imbricated in the bud. Stamens 6-21 or more. 

 Ovaries several or many, imbricated in a head, forming thick and ribbed 

 achenes in fruit, often beaked with a projecting persistent style. Mostly 

 annuals, with the habit of Sagittaria, the naked stems sparingly branched or 

 simple, and the flowers on rather short pedicels, in whorls of 3 - 6 or more. 

 Fl. summer and autumn. (Name from ^x^c65r?s, prickly, or from e'x^os, and 

 Sopos, a leathern bottle, applied to the ovary, which is in most species armed 

 with the persistent style, so as to form a sort of prickly head of fruit.) 



1. E. parvulus, Engelm. Scapes 1-3' high; shoots often creeping and 

 proliferous; leaves lanceolate or spatulate, acute (-J-1-J' long, including the 

 petiole); umbel single, 2 - 8-flowered ; pedicels reflexed in fruit; flower 3" 

 broad ; stamens 9 ; styles much shorter than the ovary ; achenes beaJcless, ob- 

 tusely few-ribbed. In mud, Mass, to Mich, and E. Minn., south to Fla. and 

 Tex. (S. Am.) 



2. E. rostratus, Engelm. Scape erect, 3' -2 high, longer than the 

 leaves ; leaves broadly ovate, cordate or truncate at base, obtuse (the blade 1-3' 

 long) ; umbel proliferous, in a branched panicle ; flower 5" broad ; stamens 12 ; 

 styles longer than the ovary ; achenes beaked, acutely many-ribbed. Swamps 

 and ditches, 111 to Fla., Mo., and Tex. A low form (var. LANCEOLATUS, 

 Engelm.) has the leaves lanceolate with an acute base. 111., Mo. 



3. E. radicans, Engelm. Stems or scape prostrate, creeping (2-4 long), 

 proliferous, bearing many whorls of flowers; leaves somewhat truncately 

 broadly heart-shaped, obtuse (2 - S' broad), long-petioled ; flowers 6 - 9" broad ; 

 stamens about 21 ; styles shorter than the ovary ; achenes short-beaked, the keeled 

 back denticulate. Swamps, 111. to N. C. and Fla., west to Mo. and Tex. 



