Taxonomy Nymphaea tuberosa. 



191 



Stipules fused, whitish, appressed, broadly triangular, slightly emarginate, with a 

 swelling near the base, 1.4 cm. long by 1.4 cm. wide. 



Rhizome horizontal, stout, 2.5 to 5 cm. in diameter, 10 cm. to 90 cm. long; color 

 pale, almost obscured by fine dark hairs ; apex protected by stipules and long fine hairs. 

 Phyllotaxy 2 on 5, becoming less evident on older parts; leaves 2 to 2.5 cm. apart. 

 Roots 8 or more from one leaf- 

 base. Branches numerous, 2.5 

 to 7 or 10 cm. apart ; originating 

 with strong connection (1.12 cm. 

 in diameter) with parent rhi- 

 zome, but the attachment later 

 becomes very slender (0.3 to 0.8 

 cm.) so that the pieces easily 

 break off, forming the so-called 

 tubers. Mature tubers 2.2 to 6 

 or 8 cm. long by 1.3 to 1.9 cm. 

 thick, occurring singly or in 

 groups of 2 to 5 from an origin- 

 ally single shoot. They are 

 loaded with starch, and show the 

 usual rhizome structure; they 

 spring from any point without 

 any visible order on the parent 

 stem; the connecting isthmus 

 shows (in transverse section) 3 

 vascular bundles with central 

 xylem, embedded in a mass of 

 large-celled, loose, starch-laden 

 parenchyma. 



Geographic Distribution. 

 North and west of the Appa- 

 lachian Mountains in North 

 America : Lake Champlain, west 

 through the Great Lakes to 

 Minnesota, south to Arkansas. 

 Very rare on the Atlantic Slope. 

 Lake Hopatcong, New Jersey, 

 fid. specimens cultivated at 

 Riverton. Poeatquissing Creek, 



Mercer County, N. J. (Abbott 1888, and our own collections). Meadville, Pa. (Britton 

 & Brown 1897). Raquette River, New York (Prentiss in Bull. Torr. Bot. C\., 10: 43- 

 45). Ontario, Canada (Britton 1889 b). Grosse Isle, mouth of Detroit River (Campbell, 

 Bull. Torr. Bot. CI., 13: 93-94, 1886). Southeastern Minnesota (Wheeler 1900). Ames, 

 Iowa (Hitchcock 1890). Swamps near Little Rock, Ark. (Branner & Coville 1888). 



Notes. A smaller variety from Lake Hopatcong, N. J., is known in gardens 



Fio. 72. Nymphaea tuberosa. Under side of leaf on right, 

 upper side on left ; 8, automatic area ; o, petiole, showing stripes ; 

 b, stipule. Natural size of leaf 24.5 cm. long; stipule reduced 

 proportionately. Petiole enlarged. 



