34 NYMPHAEACEAE [CH. 



peltate, by the further fusion of the two auricles. It recalls 

 the adult leaf of many Castalias, e.g. Castalia Lotus, Tratt. 

 It is the first leaf to bear spines. 



The succeeding leaves become more and more orbicular in 

 outline, as the auricles become fused along a successively 

 greater part of their length. As in the case of Sagittaria sagitti- 

 folia y the leaf of the mature plant passes, in its youth, through 

 stages parallel to those permanently retained by the embryonic 

 leaves. 



The flowers of the Nymphaeaceae do not show any obvious 

 relationship to their aquatic life, except perhaps in the case 

 of Euryale ferox 1 , which is described as exhibiting submerged 

 cleistogamy. The enormous flowers of Victoria regia, the Giant 

 Waterlily, apparently attract night-flying insects, but no 

 critical observations seem to have been made in the native 

 haunts of the plant. In captivity, each flower partially opens 

 one evening, closes next morning and opens 

 completely on the next evening. It remains 

 open until the hotter hours of the suc- 

 ceeding day, when it finally closes 2 . When 

 the flowers open they exhale a strong scent, 

 and much heat is also evolved ; the tempera- 

 ture of the flower may rise to 10 C. above 

 that of the surrounding air. The heat and 

 perfume are developed mainly in the 

 carmine-red, sigma-shaped outgrowths at FlG I? x ymphaealuteai 

 the apices of the carpels, apparently at the L- Fruit showing P er- 

 expense of the starch which they contain 3 . 

 The flower sinks after pollination, and the 

 fruit ripens in the water about six weeks after flowering 4 . 



The fruits and seedlings 5 of our British Waterlilies are of 

 considerable interest, although the young plants do not display 



1 Goebel, K. (1891-1893). 2 Seidel, C. F. (1869). 



3 Knoch, E. (1899). 4 Seidel, C. F. (1869). 



5 For very early and good figures of the primordial leaves of the White 

 and the Yellow Waterlily see Tittmann, J. A. (1821). 



