44 ALISMACEAE 



the leaves : whorls of the inflorescence 3-8, the 2 or 3 lower ones pistillate : pedicels 1-2.5 

 cm. long : bracts broadly ovate, 3-8 ram. long, scarious tipped : mature fruiting heads fully 

 1 cm. in diameter : achenes obliquely obovate, 2 mm. long, winged ; beak horizontal. 

 In ponds and swamps, Missouri to Alabama and Texas. Spring to fall. 



5. Sagittaria macrocarpa J. G. Smith. Monoecious. Leaves phyllode-like ; blades 

 linear or linear-lanceolate, 5-7 cm. long, much shorter than the petioles : scapes 3-4 dm. 

 tall, overtopping the leaves : whorls of the inflorescence 3-5, the lower pair, or only the 

 lowest one, pistillate : pedicels about as long as the internodes except those of the pistillate 

 flowers ; these much shorter : bracts obovate, 3 mm. long, acute, united at the base : fila- 

 ments dilated, pubescent : mature fruiting heads 10-12 mm. in diameter: achenes obovate 

 or oblong-ovate, 3 mm. long, winged ; beak ascending. 



On the margins of ponds, North Carolina and South Carolina. Spring to fall. 



6. Sagittaria isoetiformis J. G. Smith. Monoecious, delicate. Leaves terete 

 throughout, or rarely with imperfect flattish blades : scapes 8-12 cm. tall, as long as the 

 leaves or overtopping them : whorl of the inflorescence usually one : bracts ovate, 2-3 mm. 

 long, acute, united below : pedicels of pistillate flowers slender, 15-18 mm. long, those of 

 the staminate flowers filiform, 2-3 cm. long : sepals 2 mm. long : corolla white, 12-15 mm. 

 broad : filaments dilated, pubescent, about as long as the anthers : mature fruiting heads 

 about 6 mm. in diameter : achenes obovate, 1 mm. long, with a prominent dorsal crest 

 and low facial ridges ; beak short, oblique. 



On sandy margins of lakes, peninsular Florida. Spring and summer. 



7. Sagittaria teres S. Wats. Monoecious, slender. Leaves usually reduced to 

 terete attenuate nodose phyl lodes 1-3 dm. long, or rarely developing narrow, imperfect 

 blades at the top : scapes slender, 15-45 cm. tall : bracts ovate, 3 mm. long, obtuse : 

 whorls of the inflorescence solitary or sometimes 3, 1 or 2 pedicels of the lower whorls 

 bearing pistillate flowers, 10-25 mm. long, longer than those of staminate flowers : sepals 

 about 3 mm. long : corolla white, 12-15 mm. broad : stamens often 12 : filaments dilated, 

 pubescent, shorter than the anthers : mature fruiting heads 8-12 mm. in diameter : achenes 

 oval or oval-obovate, 2 mm. long, with stout obliquely upcurved beaks, an uneven crest 

 and several facial wings. 



In shallow water, Massachusetts to South Carolina. Summer and fall. 



8. Sagittaria cyclbptera (J. G. Smith) C. Mohr. Monoecious or dioecious. Leaves 

 sometimes reduced to slender tapering phyllodes ; blades linear or linear-lanceolate, 4-15 

 cm. long, tapering to both ends, shorter than the petioles : scapes 2-8 dm. long : whorls of 

 the inflorescence 3-15, or rarely solitary, several of the lower ones usually pistillate : bracts 

 ovate, 3-5 mm. long, acute, united at the base : filaments dilated, pubescent : mature fruit- 

 ing heads barely 1 cm. in diameter : achenes broadly oblong or oval, 1.5 mm. long, winged, 

 crested, with 2 facial wings on each side ; beak short, ascending, rather lateral. 



In swamps, South Carolina to Florida and Louisiana. Spring to fall. 



9. Sagittaria Mohrti J. G. Smith. Monoecious. Leaves 3-7 dm. tall ; blades linear 

 to lanceolate, 5-15 cm. long, acuminate, often poorly developed : scapes ascending, decum- 

 bent or declining, 3-angled : whorls of the inflorescence 6-8, the lower 3-4 pistillate, with 

 pedicels somewhat longer than those of the staminate flowers : bracts thin, 3-4 mm. long, 

 united to about the middle : sepals oblong, 2-3 mm. long, obtuse : corolla hardly 1 cm. 

 broad : mature fruiting heads subglobose, 6-8 mm. in diameter : achenes cuneate, 2.5-3.5 

 mm. long, winged, with cuneate crests ; beak horizontal. 



In muddy ponds, southern Alabama. Summer. 



10. Sagittaria graminea Michx. Monoecious or dioecious. Leaf-blades linear, 

 lanceolate or elliptic, 5-15 cm. long, or leaves represented by phyllodes : scapes 1-6 dm. 

 tall, shorter than the leaves or overtopping them : whorls of the inflorescence few and 

 remote or sometimes numerous and rather approximate : pedicels variable, but those of 

 staminate and pistillate flowers often equal in length : bracts ovate, 3-5 mm. long, acute, 

 united to about the middle : filaments dilated, pubescent : mature fruiting heads less than 

 1 cm. in diameter : achenes cuneate, 1.5 mm. long, winged, with one facial wing or crest ; 

 beak short, lateral, spreading. 



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



11. Sagittaria Chapmanil (J. G. Smith) C. Mohr. Monoecious or dioecious. 

 Leaves often accompanied by phyllodes ; blades linear or lanceolate, 15-20 cm. long, 

 acute, usually much shorter than the petioles : scapes 3-5 dm. long : whorls of the inflores- 

 cence often numerous : pedicels spreading or ascending, those of the pistillate heads 1.5-3 

 cm. long : bracts lanceolate, 6-12 mm. long, acute or acuminate, slightly united at the 

 base : filaments dilated, pubescent : mature fruiting heads 5 mm. in diameter : achenes 

 cuneate, 1 mm. long, wingless ; beak short, lateral and above the middle of the body. 



In ponds and marshes, Florida and Alabama. Spring to fall. 



