ALISMACEAE. 



7. Sagittaria ambigua J. G. Smith. 

 Kansas Sagittaria. (Fig. 199.) 



Sagitlaria ambigua J. G. Smith, Ann. Rep. Mo. Bot. 



Card. 6 : 48. pi. 17. 1894. 



Monoecious, glabrous, scape erect or ascending, 

 simple or sparingly branched, i-2 high. Leaves 

 lanceolate, entire, long-petioled, acute or acumin- 

 ate at both ends, seemingly pinnately veined, really 

 5-7-nerved, s'-S' long, equalling or shorter than 

 the scape ; bracts lanceolate, acuminate, 5 // -8 // 

 long, much shorter than the slender fruiting pedi- 

 cels, connate at the base, papillose ; stamens 20- 

 25 ; filaments glabrous, longer than the anthers ; 

 acheiie about i" long, oblong, curved, narrowly 

 winged on both margins, its sides smooth and even, 

 its beak short, oblique. 



In ponds, Kansas and the Indian Territory. 



8. Sagittaria lancifolia L/. Lance-leaved Sagittaria. (Fig. 200.) 



Sagittaria lancifolia L. Amoen. Acad. 5 : 409- 1760. 

 Sagittaria falcata Pursh, Fl. Am. Sept. 397. 1814. 

 Sagittaria lancifolia falcata J. G. Smith, Mem. Torr. 

 Club, 5 : 25. 1894. 



Monoecious, glabrous, scape rigid, erect, stout 

 or rather slender, striate, branched or simple, 

 longer than the leaves. Leaves lanceolate or ob- 

 long-lanceolate, acute or acuminate at both ends, 

 firm, entire, the blades s-g-nerved, S'-i^ long, 

 gradually narrowed into the long petioles, appar- 

 ently pinnately veined; flowers numerous, 5"-! 2" 

 broad; bracts ovate or ovate-lanceolate, usually not 

 united at the base, glabrous or nearly so, equalling 

 or shorter than the fruiting pedicels ; stamens 

 numerous; filaments cobwebby-pubescent, equal- 

 ling or longer than the anthers ; achene narrowly 

 obovate-cuneate, i"-!^" long, winged on both 

 margins, its sides smooth, its beak tapering, oblique. 



In swamps and shallow water, Delaware, to Florida 

 and Texas, near the coast. Widely distributed in trop- 

 ical America. 



9. Sagittaria rigida Pursh. Sessile-fruiting Arrow-head. (Fig. 201.) 



Sagittaria rigida Pursh, Fl. Am. Sept. 397. 1814. 

 Sagittaria heterophylla Pursh, Fl. Am. Sept. 396. 1814. Not 

 Schreb. 1811. 



Monoecious, glabrous, scape simple, weak, curving, 

 ascending or decumbent, shorter than the leaves. Leaves 

 very variable, linear, lanceolate, elliptic or broadly ovate, 

 acute or obtuse at the apex, entire or with I or 2 short or 

 slender basal lobes ; bracts ovate, obtuse, 2 // -4 // long, 

 united at the base or sometimes distinct ; heads of fruit 

 sessile or very nearly so ; pedicels of the sterile flowers 

 %'-i' long ; filaments dilated, mostly longer than the 

 anthers, pubescent; achene narrowly obovate, i^ // -2 // 

 long, winged on both margins, crested above, tipped with 

 a stout nearly erect beak of about one-fourth its length. 



In swamps and shallow water, Quebec to Minnesota, south to 

 New Jersey, Tennessee, Missouri and Nebraska. Petioles 

 rigid when growing in running water. July-Sept. 



