ALISNACE.E. 235 



ral, I-Cc'lled. ihniles solilarv, or in pairs, erect, or ai-cendinr^. 

 Styles sever 'd\. Fruit dry , indcliiscenl, 1-2-beedi'd. Albumen 

 none. Embryo curved. Aquatic plants, with parallel veined 

 leaves. 



Genus I SAGITTARIA. 



Flowers moncvcious. Sepals 3, herbaceous. Petals 3, col- 

 ored. Sterile tlorets with stamens nunierous. Fertile llorets 

 with capsules numerous, compressed, each l-seeded. 



1 S Sauittifoua. S/f^m none. L<titts ovate, sagittate, acute. Lohcslong, 

 acute, acuminate, lanceolate, on long petiole?, 1-2 teet. Flowers wliorled, by 

 threes, the upper ones sterile, the lower ferule. Ptlals larger than the calyx, 

 round. Stamens numerous. t'tvjAxM/ts collected into a globose head. 



The above species is very variable in the form of its leaves, and itstloN^ers 

 are sometimes dia>cious. Arruw-head. 



White. 71 Aug. — Oct. In wet places, common. 1-2 ft. 



2 S Natans. Stem none. Leuves floating, eliptic, lanceolate, obtuse, en- 

 tire, 3-nerved, alternate at the base, the lower ones somewhat cordate, 7-ncrv- 

 ed. Scape simple, few flowered, 3-6 inches long. Flowers small, the upper 

 ones sterile, the lower ones fertile, with the peduncles elongated. SejxiLs lan- 

 ceolate. Petals round. Stanuns 8. Copsulfs numerous. 



Wliite. % May — Aug. In shallow ponds 6-8 in. 



3 S Laxcifolia. Stem none. Leaves oval-lanceolate, \ery long, entire, 

 somewhat coriaceous, glabrous, on long petioles, 1-2 fieet. Scape 2-3 feet 

 long, simple- Flowers veriicillate by three?, the upper ones sterile, the lower 

 fertile. Septils tinged with purple, nearly round. Petals larger than the ca- 

 ly.\ Stamens numerous. Qtpsules numerous, collected into a globose head. 



While. % April — June. In marshes. 2-3 ft. 



4 S Graminea. Stem none. luavrs linear-lanceolate, entire, 3-nerved, 

 4-5 inches long, about half an inch wide on long petioles. Scape simple. 

 FloutTs verticHlaie, the upper sterile, the lower fertile. Sepals lanceolate, 

 small. Petals larger than the calyx. Stamens about 10, hairy. Capsules 

 mucronate. 



White. % April--June. In wet pine barrens, very '^ommon. 4-5 in. 



Genxs II ALISMA. 



Sf/)aZ5 3, persistent. Petals 3. Sta?nens6. Ovaries and 

 Styles numerous. Capsules numerous, indchiscent. distinct, 

 l-seeded. 



1 A Pr.AXTAGO. ^tem none Leaves cordate, ovale, 9-ncrved, on long 

 petioles Sc«;>^ triangular, 1-2 feet. /'7o«£«er» in compound, veriicillate pan- 

 icles. Fruit obtusely triangular. 



White. % July— Aug. In the water. 1-2 feet. 



Okuer XCVII. liYDROClIARIDE^. 



Flowers moncecious, or dioecious. Sepals 3. Petals 3. 

 Stamcjis epigynous, deiini'e. Ovary solitary, 1-celled. — 

 Ovules numerous. Stigmas 3-6. Fruit indehiscent, 1, or 



many celled. Albumen none. Floating plants, sometimes 



with spiny leaves. /'Voire r* spat haceous. 



