3. Petals broadly elliptic to narrowly oblong-elliptic, widest at about the middle, 

 somewhat tapered at both ends; rhizome without tuberlike branches 

 4. N. odorata. 



1. Nymphaea mexicana Zucc. Yellow water-lily, lampazo amarillo. Fig. 440. 



Rootstock warty with the persistent petiole bases; leaves oval to suborbicular, 

 to 2 dm. wide, glabrous, bright-green above, purple or crimson on the lower sur- 

 face; flowers 6-10 cm. wide; sepals lanceolate to narrowly elliptic-lanceolate; 

 petals usually about 25, bright-yellow, more elliptic than the sepals; stamens 50 

 to 60, the petaloid stamens mostly 2-2.5 cm. long; anthers of the inner stamens 

 4-6 mm. long; styles 7 to 9; berry ovoid, 2-2.5 cm. long; seeds 4-5 mm. in 

 diameter. TV. flava Leitn. 



In lakes, ponds and slow streams in e. and s. Tex. and Ariz. (Pinal Co.), 

 spring-summer; also s. Fla. and Mex. 



2. Nymphaea elegans Hook. Blue water-lily, lampazos. Fig. 441. 



Rootstock stoutish; leaves ovate to oval-orbicular, to 2 dm. wide, usually much 

 smaller, undulate-sinuate or nearly entire, usually dark red-purple and somewhat 

 veiny on the lower surface; flowers usually raised on a slender peduncle 1-2.5 dm. 

 above the water; sepals mostly lanceolate, 4-5 cm. long; petals 6 to 10, lanceolate 

 or sometimes ovate-lanceolate, blue or pale-violet; stamens numerous; styles 15 to 

 25, mere blunt protuberances; berry depressed-globose, 1.5-3 cm. in diameter; 

 seeds 1-1.5 mm. in diameter. Castalia elegans (Hook.) Greene. 



In ponds, pools and ditches in s. Tex., Apr-July; also s. Fla. and Mex. 



3. Nymphaea tuberosa Paine. 



Rather coarse plant; rhizome with readily disarticulating branches strongly con- 

 stricted at base and tuberlike; petioles green, striped above with brown; leaf blades 

 green beneath or rarely dull purple, flat and floating or somewhat elevated above 

 the water, 1-4 dm. across; flower odorless or scarcely fragrant, 1-2.5 cm. broad, 

 opening for 3 or 4 days from early morning to early afternoon; sepals green on 

 the back; petals oblanceolate to subspatulate, obtusely rounded at summit; filaments 

 broader than their anthers; seeds 2.8-4.4 mm. long. 



Pond margins and slow streams in Okla. (Ottawa Co.), June-Sept.; from s.w. 

 Que. to n. Ont., Minn, and Neb., s. to Md., O., Ind., lU., Ark. and Okla. 



4. Nymphaea odorata Ait. White water-lily, alligator-bonnet, ninfa 



ACUATiCA. Fig. 442. 



Rhizome stout, horizontal, elongate, mostly 2.5-3 cm. thick; leaves arising 

 along the rhizome, suborbicular, to 25 cm. wide, with a narrow sinus, green above, 

 green tinged with red or purplish-red and obscurely veined on the lower surface; 

 flowers very fragrant; sepals often purplish on back, elliptic to ovate or ovate- 

 lanceolate, to 8 cm. long and 25 mm. wide; petals usually more than 25, white, 

 elliptic or slightly broadened upward, thickish; stamens mostly more than 70, the 

 petaloid stamens 3-4 cm. long; styles mostly about 20; berry depressed-globose, 

 mostly 2.5-3 cm. in diameter; seeds ellipsoid, about 2 mm. long. Incl. var. villosa 

 Casp. and var. gigantea Tricker, N. spiralis Raf., N. lekophylla (Small) Cory, 

 Castalia odorata (Ait.) Woodv. & Wood, C. lekophylla Small. 



In ponds, lakes, slow streams and ditches in Okla. (Comanche and LeFlore cos.), 

 e. Tex. and Ariz. (Yavapai Co.), Mar.-Oct.; from Fla. to Tex., n. to e. Can. and 

 Man.; Ariz. 



902 



