1955] 



REVISION OF THE GENUS SAGITTARIA 



227 



Sagittaria art folia Nutt. ex J.G.Sm. Missouri Bot. Gard. Rep. 6: 6. 1894. 

 Sagittaria ari folia var. stricta J.G.Sm. Missouri Bot. Gard. Rep. 6: 8. 1894. 

 Sagittaria ari folia var. aquatilis J.G.Sm. Missouri Bot. Gard. Rep. S>: 156. 1898. 

 Sagittaria hebetiloba A. Nels. Bull. Torrey Club 26: 6. 1899. 

 Sagittaria paniculata Blankin. Mont. Coll. Sci. Stud. Bot. 1: 40. 1905. 

 Sagittaria arifolia var. tenuor Blankin. Mont. Agr. Coll. Sci. Stud. Bot. 1: 40. 1905. 

 Sagittaria arifolia var. cuneata (Sheld.) Lunell, Bull. Leeds Herb. 1: 3. 1907. 

 Sagittaria arifolia var. dimorpha Lunell, Bull. Leeds Herb. 1: 3. 1907. 

 Sagittaria arifolia var. monomorpha Lunell, Bull. Leeds Herb. 1: 3. 1907. 

 Sagittaria arifolia var. polymorpha Lunell, Bull. Leeds Herb. 1: 3. 1907. 

 Sagittaria hitchcockii Gandoger, Bull. Soc. Bot. Fr. 66: 294. 1919. 

 Sagittaria suksdorfii Gandoger, Bull. Soc. Bot. Fr. 66: 294. 1919. 



Perennial with runners and corms. Leaves emersed, floating, or submerged. 

 Emersed leaves sagittate, with lanceolate to ovate deltoid blades 2.5" 17 x 1.5-11 

 cm, the deltoid basal lobes 0.7-11 x 0.7-6 cm, the floating leaves commonly cor- 

 date, rarely linear to ovate, the submerged leaves modified into ribbon-shaped 

 phyllodia to 45 cm long, the petioles 5-70 cm long. Scape 10-50 cm or more long, 

 with 2-8 whorls of flowers, occasionally branching at the lowest whorl. Bracts 

 more or less membranous, joined at the base, (0.4- )0. 7-3. 5 cm long, lance- 

 attenuate or acute. Pistillate pedicels ascending, 0.5-2 cm long, the staminate 

 somewhat longer. Sepals reflexed, 0.4-0.8 cm long. Petals white, ca. 1.5 times as 

 long as the sepals. Stamens 15-24, the glabrous subulate filaments 0.8-2 mm 

 long, about equaling the oblong anthers. Mature receptacle 0.8-1.5 cm in diameter; 

 achenes obovate, 1.8-2.6 x 1.3-2 mm, the prominent rounded dorsal wing to 0.8 

 mm wide, exceeding the strongly rounded ventral wing, the faces plain, or with a 

 low slender rib, the apical subulate erect beak 0.1-0.4 mm long. (FIG. 20a-c.) 



Type, collection: Aug. 1892, Sheldon s.n., East Battle Lake, Ottertail Co., 

 Minnesota (holotype Minn.; isotypes GH, MO, NY, UC, US). 



Distribution: Subarctic Canada, south to New England, New York, Great Lakes, 

 Iowa, Kansas, Texas, New Mexico, Arizona, and California. The plant is wide- 

 spread on calcareous and muddy shores and the shallow waters of diverse fresh- 

 water habitats, occasional in tidal waters. S. cuneata is the common species of 

 Canada and the northern United States and the only Sagittaria of the Rocky Moun- 

 tains and the Great Basin. Collections examined from Alberta, British Columbia, 

 Manitoba, New Brunswick, Nova Scotia, North West Territory, Ontario, Quebec, 

 and Saskatchewan in Canada, and Arizona, California, Colorado, Connecticut, 

 Idaho, Illinois, Indiana, Iowa, Kansas, Maine, Massachusetts, Michigan, Minnesota, 

 Montana, Nebraska, Nevada, New Hampshire, New Mexico, New York, North 

 Dakota, Ohio, Oregon, South Dakota, Texas, Utah, Vermont, Washington, Wisconsin, 

 and Wyoming in the United States. (FIG. 20.) 



Sagittaria cuneata is extremely plastic vegetatively but relatively constant 

 florally. It is immediately recognized in maturity by the unique round-winged 

 achenes with short, erect beaks. It is the only temperate New World species with 

 cordate floating leaves. 



Its closest relationships are with S. latifolia and S. enge Imanniana in the New 

 World and S. sagittifolia in the Old World. Until relatively recent times S, cuneata 

 probably formed a circumboreal species with the latter. Indeed there still may be 

 some justification for considering it a subspecies of S. sagittifolia. The key dif- 

 ferences between the two are quite well defined and show no variation within their 



Explanation of Figures 19, 20 



FIG. 19. Distribution of S. longiloba. a, achene, X 3. b, bracts, X %» c, stamen, X 3. 

 FIG. 20. Distribution of S. cuneata* a, achene, X 3. b, bracts, X 1. c, stamen, x 7. 



