7(5). Achene beak laterally inserted, more or less projecting horizontally (8) 



7. Achene beak apically inserted, more or less erect (10) 



8(7). Bracts of inflorescence cymbiform, obtuse to acute, rather firm, sometimes 

 pubescent; achene beak 0.5 mm. long or more 7. S. ladfolia. 



8. Bracts of inflorescence almost plane, at least not cymbiform, acuminate to 



attenuate, membranous, never pubescent; achene beak Jess than 0.5 

 mm. long (9) 



9(8). Achenes without or with solitary facial wings; leaf blades not more than 

 2.5 dm. long, the terminal lobe linear to lanceolate, usually long- 

 acuminate, commony less than half as long as the basal lobes; 

 scape usually simple 8. S. longiloba. 



9. Achenes with facial wings and tuberculations; leaf blades typically 2-4 dm. 



long, the terminal lobe ovate to broadly lanceolate, acute to short- 

 acuminate, more than half as long as the basal lobes; scape some- 

 times branched 9. S. Greggii. 



10(7). Achene usually with one narrow facial wing or keel, the beak somewhat 

 curved and 0.5 mm. or more long 10. S. brevirostra. 



10. Achene face wingless, typically with a large resin duct, the minute to obso- 



lescent beak erect 11. S. cuneata. 



1. Sagittaria montevidensis Cham. & Schlecht. Fig. 61. 



Emersed aquatic annual, only the early stages completely submersed, erect, to 

 5 dm. tall; leaves erect-spreading, usually with stout spongy petioles; leaf blades 

 broadly ovate, sagittate, to 2 dm. or more long and wide; scape erect or reflexed, 

 simple or occasionally branched below, with up to 10 whorls; bracts membranous, 

 ovate to ovate-lanceolate, acute to attenuate, connate, about 1 cm, long; pistillate 

 flowers usually with a ring of functional stamens; sepals orbicular-ovate, concave, 

 about 13 mm. long, covering most of the fruiting head; stamens with linear 

 pubescent filaments; heads of carpels to 2 cm. in diameter; achenes cuneate- 

 obovate, to 2.5 mm. long and 1.3 mm. wide, the faces usually with a resin duct, 

 the horizontal or oblique beak about as long as the breadth of the achene and 

 narrowly winged on the margin. 5. calycina Engelm., Lophotocarpus calycinus 

 (Engelm.) J. G. Sm. 



Sloughs, lakes and ponds in e., cen. and w. Tex., Okla. (Adair, Sequoyah, 

 Cherokee, Murray and Johnston cos.) and N.M., June-Oct.; O. and Mich., w. 

 to N.D., Calif, and N.M., s. to Va., Tenn., La. and Tex. 



Our plants have been segregated as subsp. calycina (Engelm.) Bogin. 



2. Sagittaria graminea Michx. Fig. 62. 



Leaves erect, either represented by thin broadly linear (strap-shaped) acute to 

 shortly acuminate phyllodia or with the slender petioles bladeless or with nar- 

 rowly lanceolate tapering blades to 2 dm. long and 25 mm. wide; scape simple, 

 usually surpassed by the leaves, with as many as 10 whorls, the flowers with fili- 

 form ascending or spreading pedicels to 3 cm. long, the lower one or two whorls 

 of pistillate flowers or sometimes all staminate; bracts ovate, obtuse to subacute, 

 to 6 mm. long, more or less connate, membranous; sepals ovate, obtuse, to 5 mm. 

 long; petals white or rarely pinkish, to 6 mm. long; stamens with dilated pubescent 

 filaments to 1 mm. long; fruiting heads to 1 cm. in diameter; achenes obovate, to 

 2 mm. long and 1.2 mm. wide, the narrow-winged back strongly rounded to a 

 high shoulder, the sides plane or with 1 or 2 narrow ridges, the subulate beak to 

 0.3 mm. long, obliquely inserted below the summit of the achene. S. cycloptera 

 (J. G. Sm.) Mohr. 



Rooted in mud or in shallow water of ditches, ponds, marshes and streams in 

 e. and s.-cen. Tex. and Okla. (Osage Co.) to s.e. Ariz., flowering throughout 

 the year but mostly Apr.-Nov.; throughout e. N. A., w. to the Great Plains; also 

 Cuba. 



145 



