142 



THE WATERLILIES. 



DESCRIPTION. Flowers 7 to 17 cm. across, light blue, with a faint and character- 

 istic sweet odor, open on 3 days from 7.30 a. m. to 12 m. (4 days, 8 a. m. to 2 p. m. 

 Casp. 1877). Bud distinctly conical, with straight sides, obtuse, abruptly contracted 

 below to the receptacle, 7 cm. long by 2.5 cm. in diameter at base. Receptacle nearly 

 three times as wide as peduncle, spreading out at about 45 from the vertical, pale 

 purplish green. Peduncle terete, 0.6 to 0.8 cm. in diameter, 18 to 38 cm. long, most 

 slender about 1.25 cm. below flower, smooth, dull brownish-green: main air-canals 6, 

 surrounded by a circle of 12 smaller ones. Sepals 4, broadly lanceolate, breadth : length 

 = i : 2.8 to 4.7, the sides nearly straight in upper two-thirds, somewhat converging 

 below to the broad base; apex rounded. Outer surface dark green, thickly necked 

 with purplish-black dots and lines most dense near margins of sepal and midway of 

 length ; the green ground-color assumes a yellowish tint near base of sepal. Seven 



Fia/55. Nymphaca caerulea: a, closed flower; li, sepal; c, d, e, outer, median, and inner petals; 

 /, ?i, stamens ; g, carpellary style viewed en face ; t, vertical section of ovary ; k, vertical section of fruit. 

 Eeduced about one-half. 



longitudinal veins can be seen by looking through the sepal at the light. Inner surface 

 dull white, tinged blue on midline near apex, greenish and veiny and semi-translucent 

 in lowest three-quarters of length. Petals 12 to 20, of moderately firm texture, open- 

 ing about 30 above horizontal, about as long as the sepals. They stand in 3 series: 

 first, a whorl of 4, alternate with the sepals; second, a whorl of 8, one on each side of 

 each outer petal ; third, a whorl of 8 alternate with the second, but usually imperfect, 

 consisting of only 2 to 5 petals on one side of the flower, rendering it so far unsym- 

 metrical. Outermost petal narrowly elliptic-lanceolate, obtuse, with rather broad in- 

 sertion (0.8 cm. in Flower No. 3, see table of measurements), not at all concave; outer 

 surface colored on lower half and on the midline dark green with black spots exactly 

 like the sepals ; one-third of width at margin on each side, above, colored pale blue ; 

 inner surface white on lower half, becoming translucent and 7-veined at base, shading 

 above to a pale sky-blue at apex and on upper margins. Petals of second whorl 

 shorter than those of the first, rhombic-lanceolate, narrowed at apex and base, 5-veined 



