ALISMACEAE 45 



Filaments glabrous. 



Basal lobes of the leaf-blades acute or acuminate. 22. S. loiigirostra. 



Basal lobes of the leaf-blades rounded. 23. S. australis. 



Sepals of the pistillate flowers accrescent and ultimately appressed to the 



fruit-heads. 24. S. Montevidensis 



1. Sagittaria subulita (L.) Buch. Leaves erect; blades linear or linear- 

 lanceolate, 2-3 cm. long, or wanting, the phyllodia slender: scapes 5-15 cm. tall, 

 with 1 or 2 flower-whorls: achenes few, about 1.5 mm. long, the beak ascending. 



In mud and tidal flats, Connecticut and New York to Florida and Alabama. 



2. Sagittaria lorata (Chapm.) Small. Leaves floating; blades elliptic, oblong 



or ovate-oblong, 1.5-5 cm. long, or wanting, the phyllodia stout: scapes 1-10 dm. 



long, with 1 or several flower-whorls: achenes numerous, about 2 mm. long, the beak 



erect. [*S'. natans Michx. Not Pall.] 



In streams or fresh or brackish ponds, South Carolina and Florida. Also in New 

 Jersey and New England. 



3. Sagittaria filifdrmis J. G. Smith. Leaf -blades wanting: scapes 6-12 dm. 

 long, with several flower-whorls: only 1 or 2 flowers of the lower whorl pistillate, 

 their pedicels elongated: fruit-heads 6-7 mm. thick: achenes 1.5 mm. long, about 

 6-crested_, the beak curved up. 



In ponds, Florida and Alabama ; apparently also in the Carolinas. 



4. Sagittaria platyphylla (Engelm.) J. G. Smith. Leaf -blades lanceolate, 

 elliptic or ovate, 5-15 cm. long: scapes 2-5 dm. tall, with 3-8' flower-whorls, the 

 flowers of 2 or 3 lower whorls pistillate, their pedicels very short: fruit-heads fully 

 10 mm. thick: achenes 2 mm. long, winged, the beak horizontal. 



In ponds and swamps, Missouri and Kansas to Alabama and Texas. 



5. Sagittaria t^res S. Wats. Leaf -blades narrow and imperfect, or wanting: 

 scapes 1.5-4.5 dm. tall, with 1 or rarely 2 or 3 flower-whorls, 1 or 2 flowers of the 

 lower whorl pistillate : fruit-heads 8-12 mm. thick : achenes 2 mm. long, unevenly 

 crested, the beak nearly erect. 



In shallow water, Massachusetts to South Carolina. 



6. Sagittaria isoetifdrmis J. G. Smith. Leaf -blades wanting or imperfect : 

 scapes 7-12 dm. tall, usually with 1 flower whorl: fruit-heads about 6 mm. thick: 

 achenes 1 mm. long, dorsally crested, the beak oblique. 



In low grounds and sandy lake margins, Georgia and Florida. 



7. Sagittaria cycldptera (J. G. Smith) C. Mohr. Leaf-blades linear or linear- 

 lanceolate, 4-15 cm. long, or wanting: scapes 2-S dm. long, mainly with 3-15 flower- 

 whorls: fruit -heads barely 10 mm. thick: achenes 1.5 mm. long, the minute beak 

 ascending. 



In swamps. South Carolina to Florida and Louisiana. 



8. Sagittaria Mohrii J. G. Smith. Leaf -blades linear to lanceolate, 5-15 cm. 

 long, sometimes imperfect: scapes 4-9 dm. long, with 6-8 flower-whorls: fruit-heads 

 6-8 mm. thick: achenes 2.5-3.5 mm. long, the minute beak horizontal. 



In ponds, Georgia and Florida to Mississippi. 



9. Sagittaria graminea Michx. Leaf-blades linear, lanceolate or elliptic, 5-15 

 cm. long, or wanting: scapes 1-6 dm. tall, with few or many flower- whorls: fruit- 

 heads less than 10 mm. thick: achenes 1.5 mm. long, winged, the minute beak 

 horizontal. 



In mud or ponds, Newfoundland to Saskatchewan, Florida and Texas. 



10. Sagittaria Chapminii (J. G. Smith) C. Mohr. Leaf -blades linear or lance- 

 olate, 15-20 cm. long, or wanting: scapes 3-5 dm. long, with often many flower- 

 whorls and paniculate : fruit-heads 5 mm. thick : achenes 1 mm. long, wingless, the 

 minute beak lateral. 



In ponds and marshes, Georgia, Florida and Alabama. 



11. Sagittaria papillosa Buch. Leaf-blades linear to linear-lanceolate, 10-15 

 cm. long: scapes 3-5 dm. tall, with 3-10 flower-whorls: fruit -heads 6-10 mm. thick: 

 achenes cuneate, 1.5 mm. long. 



In shallow ponds, Louisiana and Texas. 



12. Sagittaria ambigua J. G. Smith. Leaf -blades lanceolate, 12-50 cm. long: 

 scapes 3-6 dm. tall, with mostly 8-15 flower-whorls: fruit heads 11-15 mm. thick: 

 achenes 2 mm. long, narrowly winged. 



In ponds, Kansas and Oklahoma. 



13. Sagittaria falcata Pursh. Leaf -blades narrowly elliptic, sometimes slightly 

 broadest above the middle, or nearly linear, 10-35 cm. long, mainly 3-5-nerved: 

 pedicles of the pistillate flowers relatively short, their bracts of an ovate type: 

 achenes about 2 mm. long. 



In low grounds and marshes, Delaware to Florida. Texas and Mexico. 



