ALISMACEAE 45 
12. Sagittaria papillósa Buch. Monoecious. Leaf-blades linear or linear-lanceo- 
late, 10-15 cm. long, acute, as long as the petioles or shorter : scapes 3-5 dm. tall: whorls 
of the inflorescence 3-10, the lower remote: pedicels of pistillate flowers 1-1.5 cm. long: 
bracts ovate, 3-4 mm. long, densely granular-papillose, united to about the middle : sepals 
ovate, roughened like the bracts : corollas:2-3 cm. broad : filaments not dilated, glabrous : 
mature fruiting heads subglobose, 6-10 mm. in diameter: achenes cuneate, 1.5 mm. long ; 
beak lateral and slightly above the middle of the body. 
In shallow ponds, Louisiana and Texas. Spring to fall. 
13. Sagittaria ambígua J. G. Smith. Monoecious. Leaves erect ; blades lanceo- 
late, 12-50 cm. long, 5-nerved, shorter than the petioles: scapes 3-6 dm. tall, as long as 
the leaves or surpassing them: whorls numerous, commonly 8-15: pedicels mostly ascend- 
ing, those of the pistillate heads longer than those of staminate ; bracts lanceolate, 10-15 
mm. long, united at the bases : filaments not dilated, glabrous : achenes oblong, slightly 
curved, 2 mm. long, narrowly winged, prolonged into short horizontal beaks at the top. 
In ponds, Kansas and Oklahoma. Summer. 
~~ 14. Sagittaria lancifólia L. Monoecious. Leaves 4-9 dm. tall; blades leathery, 
broadly linear to elliptic, 3-6 dm. long, acute, commonly shorter than the petioles: scapes 
6-20 dm. tall, usually branched: whorls of the inflorescence numerous : pedicels of the 
pistillate heads ascending, often shorter than those of the staminate : bracts ovate or ovate- 
lanceolate, 1-2.5 cm. long, acute or acuminate: sepals obtuse: corollas 4-5 cm. broad ; 
petals obovate : filaments not dilated, pubescent : mature fruiting heads fully 1 cm. in diam- 
eter: achenes cuneate or obovate, 2-3 mm. long, winged ; beak short, ascending. 
In marshes, Delaware to Florida, Texas and tropical America. Spring and summer. 
15. Sagittaria rigida Pursh. Monoecious. Leaf-blades 5-20 cm. long, linear, lance- 
olate, elliptic or broadly ovate, 7-9-nerved, acute or cordate at the base, sometimes with 
1 or 2 spreading or recurved basal lobes : scapes 1-8 dm. long, commonly shorter than the 
leaves, usually bent and sometimes branched at the lower whorl of the inflorescence : pedi- 
cels of the pistillate heads (1 or 2 lower whorls) barely 1 cm. long: bracts ovate, obtuse, 
4-8 mm. long, united at the base: mature fruiting heads 8-15 mm. in diameter, bristly by 
the protruding beaks of the achenes : achenes cuneate, 3-4 mm. long, winged ; beak stout, 
ascending. 
In swamps or running water, Quebec to Minnesota, New Jersey, Tennessee and Nebraska, Sum- 
mer and fall. 
16. Sagittaria longiloba Engelm.  Monoecious, glabrous. Leaf-blades 10-18 cm. 
long ; terminal lobe linear to lanceolate ; basal lobes linear or linear-lanceolate, twice or 
thrice as long as the terminal one, long-acuminate : scapes 3-15 dm. tall, rarely branched : 
whorls of the inflorescence 4-8, remote, 1-3 lower very fertile : pedicels slender, 15-35 mm. 
long, spreading: bracts lanceolate, 6-8 mm. long, acuminate : filaments not dilated, gla- 
brous : mature fruiting heads 10-15 mm. in diameter : achenes cuneate, 1 mm. long ; wings 
somewhat undulate ; beak very short, lateral. 
On margins of shallow ponds, Nebraska to Colorado, Texas and Mexico. Summer and fall. 
17. Sagittaria longiróstra (Micheli) J. G. Smith. Monoecious, glabrous. Leaf- 
blades rather ample, 10-25 cm. long ; terminal lobe broadly ovate, abruptly pointed ; basal 
lobes ovate or oblong-lanceolate, acute, about 3 as long as the blade: scapes 4-8 dm. tall, 
sharply 6-angled: whorls of the inflorescence few, 1 or 2 lower ones usually pistillate : 
bracts triangular, 15-30 mm. long, acuminate: pedicels of the lower whorls 5-10 mm. 
long, ascending: mature fruiting heads spheroidal, 12-18 mm. in diameter: achenes 
obovate, 4 mm. long, the crest undulate ; beak about 3 as long as the body, curved ; facial 
wings prominent. 
On margins of ponds, New Jersey and Pennsy!vania to Tennessee. Summer. 
18. Sagittaria viscósa C. Mohr. Monoecious. Leaf-blades broadly ovate, 2-3.5 dm. 
long, rounded to the apiculate apex ; basal lobes ovate, acute or acuminate, shorter than 
the middle lobe : scapes 5-8 dm. tall, overtopping the leaves: pedicels in 8-10 whorls, of 
nearly equal length throughout: bracts leathery, ovate-oblong, obtuse, papillose, rugose 
and viscid : sepals leathery, ovate-lanceolate, roughened and viscid like the bracts : corol- 
las white, fully 1 em. broad : filaments not dilated, pubescent : achenes not seen. 
In muddy plases and marshes, southern Alabama. Spring and summer. 
19. Sagittaria australis (J. G. Smith) Small. Monoecious, slender. Leaf-blades 
oval or suborbicular, 8-10 cm. long, abruptly pointed at the apex, ciliate; basal lobes 
ovate, barely 3 as long as the blade, obtuse: scapes 4-5 dm. tall, pubescent about the 
nodes in the inflorescence, angled, overtopping the leaves : whorls of the inflorescence 4-6, 
remote: bracts lanceolate or ovate-lanceolate : pedicels of lower whorls 10-13 mm. long: 
achenes obovate, 3-3.5 mm. long ; crest undulate ; beak curved over the top of the crest, $ 
