36 NYMPHAEACEAE [CH. 



a rich starch content, which diminishes as the mucilage is 

 developed suggesting that the mucilage is formed at the 

 expense of the starch. 



By November 24, 1914, the loculi under observation had 

 mostly decayed completely, and the seeds were set free. They 

 remained dormant throughout the winter, but by April 23, 

 1915, a large number had germinated and there was a forest 

 of slender, grass-like, first leaves arising from the bottom of the 

 bell-jar. Seedlings at this stage are shown in Fig. 1 8 ^,p. 35 ; the 

 seed-coat opens by means of an operculum (0) to emit the radicle. 

 During the summer these seedlings developed a number of 

 submerged leaves with lanceolate blades (Fig. 18 B\ which 

 increased in number until, on September 18, some of the 

 plants had as many as seven such leaves. In spite of the unna- 

 tural conditions under which they were living, many of the little 

 plants survived the winter and, by the spring of 1 9 1 6, they had 

 developed distinct but miniature rhizomes marked with leaf- 

 scars. The leaves were still of the submerged type only. But the 

 most interesting event of this second spring was the germina- 

 tion of a very large number of seeds which had remained dor- 

 mant for eighteen months. This delay in the sprouting of the 

 seeds is not unusual in water plants (see p. 243). Unfortunately 

 the frost of the very severe winter 19161917 destroyed the 

 aquarium, and these observations came to an abrupt end. 



Vegetative reproduction, though not so universal among 

 Waterlilies as in some other groups of aquatics, is by no 

 means rare. In certain cases tubers are formed as part of the 

 ordinary course of development of the species, while in Castalia 

 Lotus 1 the flowers may, under the abnormal conditions due to 

 cultivation, be replaced by tubers which can reproduce the 

 plant (Fig. 19). Like the seedlings, these young plants deve- 

 loped from a germinating tuber have a simple type of first 

 leaf ft). 



The anatomy of the Nymphaeaceae has been investigated by 



1 Barber, C. A. (1889). 



