1955] 



REVISION OF THE GENUS SAGITTARIA 



219 



This plant has been known under the name of S. mexicana Steud. on the basis 

 that S. macrophylla Zucc. was a later homonymn of 5. macrophylla Bunge, which 

 itself is a synonym of 5". sagittifolia. This belief was based on the misconcep- 

 tion that Bunge's publication dates from 1831 instead of 1833. 



15. Sagittaria latifolia Willd. Sp. PI. 4: 409. 1805. 



Plant glabrous or variously pubescent, Perennial with rhizomes and/or runners 

 and corms. Leaves emersed or submerged, the emersed occasionally linear to 

 ovate, mostly sagittate with linear to ovate- triangular blades 3-26 x0.7-26 cm, 

 the basal lobes 2-24 x 0.5-15 cm, linear to ovate-triangular, the submerged rare, 

 modified into linear phyllodia to 60 cm long, the petioles to 100 cm long. Scape 

 15-80 cm long, with 2-7(-10) whorls of flowers, occasionally branching from the 

 lowest whorl. Bracts 0.4-0.9(-1.5) cm long, boat-shaped, joined at the base or 

 nearly free. Pedicels ascending, 0.5-6 cm long. Sepals reflexed, 0.5-1.1 cm long. 

 Petals white, ca. twice as long as the sepals. Stamens 21-°s the glabrous more 

 or less linear filaments 1-3.7 mm long, the oblong anthers 1-2.3 mm long. Mature 

 receptacle 1-2.5 cm in diameter; achenes obovate, 2.5-4 x 1.5-2.5 mm, the occa- 

 sionally crested dorsal wing 0.4-0.8 mm wide, the ventral wing somewhat narrower, 

 the faces with a resin duct and/or a low rib, or frequently unadorned, the gradually 

 tapering, laterally inserted beak 0.6-1.6 mm long. 



1. Plant glabrous throughout; widespread. 15a. var. latifolia. 



1. Plant more or less pubescent throughout; southeastern United States. 



15b. var. pubescens. 



15a. Sagittaria latifolia var. latifolia. 



Sagittaria obtusa Muhl. ex Willd. Sp. Pi. 4: 409. 1805. 

 Sagittaria sagittifolia var. latifolia (Willd.) Muhl. Cat. 86. 1813. 

 Sagittaria latifolia var. major Pursh, Fl. Am. Sep:. 2: 396. 1814. 

 Sagittaria hastata Pursh, Fl. Am. Sept. 2: 396. 1814. 

 Sagittaria gracilis Pursh, Fl. Am. Sept. 2: 396. 1814.. 

 Sagittaria simplex Pursh, Fl. Am. Sept. 2: 397, p.p. 1814. 

 Sagittaria sagittifolia var. gracilis (Pursh) Torr. Comp. 355. 1826. 

 Sagittaria sagittifolia var. hastata (Pursh) Torr. Comp. 355. 1826. 

 Sagittaria sagittifolia var. macrophylla Hook. Fl. Bor. Am. 2: 167. 1840. 

 Sagittaria sagittifolia var. vulgaris Hook. Fl. Bor. Am. 2: 167. 187. 1840. 

 Sagittaria variabilis Engelm. in A. Gray, Man. Bot. 461. 1848. 



Sagittaria variabilis var. angustifolia Engelm. in A. Gray, Man. Bot. ed. 2. 439. 1856. 

 Sagittaria variabilis var. diversifolia Engelm. in A. Gray, Man. Bot. 439. ed. 2. 1856. 

 Sagittaria variabilis var. gracilis (Pursh) Engelm. in A. Gray, Man. Bot. ed. 2. 439. 

 1856. 



Sagittaria variabilis var. sagittifolia Engelm. in A. Gray, Man. Bot. 439. ed. 2. 1856. 

 Sagittaria variabilis var. hastata (Pursh) Engelm. in A. Gray, Man. Bot. ed. 5. 493. 

 1867. 



Sagittaria sagittifolia var. variabilis (Engelm.) Micheli in DC. Monogr. Phan. 3: 69, 

 P.p. 1881. 



Sagittaria latifolia var. glabra Buch. Pflanzenreich 4(15): 50. 1903. 

 Sagittaria esculenta HowelJ, Fl. NW. Am. 1: 679. 1903. 

 Sagitta latifolia (Willd.) Nieuwl. Am. Midi. Nat. 3: 22. 1913. 

 Sagittaria latifolia var. obtusa (Muhl.) Wieg. Rhodora 27: 186. 1925. 

 Sagittaria ornithorhyncha Small, Man. SE. Fl. 25. 1933. 

 Sagittaria planipes Fernald, Rhodora 49: 106. 1947. 

 Sagittaria sagittifolia Auct. non L. 



Plant glabrous throughout. (FIG. 17a-d.) 



Type collection: Muhlenberg s.n., 'Canada' (holotype, not seen, presumably at 

 Berlin; frag, of holotype US). 



Distribution: Cold- temperate Canada, south to northwestern South America; 

 absent in the Rocky Mountains, sporadic in the southeastern United States, in- 



