190 



The Waterlilies. 



The germinating tuber produces at first 3 or 4 tliin and fragile submerged leaves. 

 The first is broadly deltoid, rounded or emarginate at apex, truncate at base, 2.9 to 

 3.8 cm. wide at base by 1.6 to 1.9 cm. long on a slender petiole 7 to 12 cm. long. The 

 second is similar to the first or may be much larger, somewhat drawn in at the peti- 

 ole, approaching a hastate shape, 6.4 cm. wide by 3.8 cm. long. Third and fourth 

 leaves hastate, rounded at apex, 5.4 cm. wide at base by 6.4 cm. long, the sinus 1.9 

 cm. deep. The first floating leaf is orbicular-ovate, entire, with rounded apex, open, 

 straight narrow sinus with lobes produced and acuminate, 5.7 to 7.6 cm. in diameter. 

 By degrees the mature foliage is attained. 



Leaf of mature plant floating, or sometimes borne 2 to 7 cm. above the water, 

 cleft to the petiole, less leathery in texture than in N. odorata, orbicular, 12 to 38 cm. 



Fig. 71. Nymphaea tuberota: (a) group of tubers; 1, S, 3, first, second, and third submerged leaves from 

 sprouting tuber. Natural size. 



across, entire, or slightly curved outward at apex, smooth, bright green and some- 

 what veiny above (purplish and shiny when very young), darker in color over the 

 point of insertion of the petiole. Under surface mostly smooth, pitted toward the 

 center (sometimes pubescent, Britton & Brown, 1. c), always green at maturity, 

 slightly purplish toward margins when young; veins rather prominent, 7 to 13 on each 

 side; length of principal area: radius of leaf =1:1.6. Sinus depth: length of leaf = 

 1 : 2.3, open or closed, margins gently curved, touching at proximal end, 3.2 to 6.4 cm. 

 wide at periphery of leaf, angles short-acuminate, abrupt on outer side, obtuse at 

 point. Petiole pubescent when very young, smooth at maturity, terete or a little flat- 

 tened ventrally, with 1 or 2 longitudinal ridges, 30 cm. to 2 m. long, 0.6 to 0.9 cm. 

 in diameter; 4 main air-canals surrounded by 12 smaller ones; idioblasts in very 

 small number, about 40 in central quadrangle 1 cm. below leaf. Color green, with 

 12 to 24 longitudinal brown stripes due to pigment dissolved in subepidermal tissue, 

 running from near the leaf downward 1 or 2 dm. or even the whole length of the 

 petiole ; about one-half of the stripes are broader and more prominent than the rest. 







