io6 The Waterlilies. 



represents the plumule, and a similar prominence opposite (next to the 

 suspensor) is the radicle. Subsequently the cotyledons spread round the 

 walls of the endosperm and fill up all of the limited space available, while 

 between them the two leaf-rudiments of the plumule are differentiated. 



GERMINATION AND EARLY GROWTH. 



Corresponding with the habits of life of the various species of Nym- 

 phaea are certain requirements for the proper growth of seedlings. Seeds 

 of the Eu-castalia group quickly lose the power of germination if dried ; in 

 nature only those which are, by chance freshets, stranded hopelessly above 

 the normal water level ever become dry. N. tetragona can withstand 

 drought fairly well. Seeds from Kashmir communicated by Mr. Wm. Gollan, 

 of Saharanpur, India, germinated quite well, but of several sendings received 

 in the early spring of successive years from Japan, only one seed has ever 

 sprouted. The former were sent to us directly after they were gathered, 

 while the latter have doubtless been kept in a seed-house since the 

 previous summer. Seeds of the Lotos and Brachyceras group can with- 

 stand a great deal of drought ; they are accustomed to it ; but they are 

 kept much more successfully, as Caspary (1877) recommended, packed in 

 clay and air dried. Under these conditions a considerable amount of 

 moisture is retained, even when the mass appears to be perfectly dry. 

 N. zanzibariensis was introduced into Europe from Zanzibar by seeds 

 packed in chalk ; and of a box of seeds of N. dentata, mingled with soil, re- 

 ceived last summer (1901) from Jamaica, nearly every one sown germinated. 

 In all of the Castalia group the seeds should be kept in bottles of water. 

 It was thus, also, that Victoria regia was successfully carried to England 

 after a long series of costly failures. 



For germination the seeds of waterlilies need to be submerged in 5 

 to 30 cm. of water. Those of the Castalia group prefer a temperature of 

 15 to 18 R., but the tropical species do best at 23 R. (Siber, 1883). A 

 very irregular length of time is required. Of a quantity of N. elegans X 

 zanzibariensis seeds sown as soon as collected, a large number came up 

 in two weeks ; after more than a year some earth from this pot chanced to 

 be placed in a warmer tank, and numerous new and vigorous seedlings 

 appeared. In the Dreer Gardens at Riverton, N. J., I have seen flowering 

 plants of N, caerulea which came up spontaneously out of doors where 

 two years previously that species had been grown ; the seeds had lain 

 dormant over all one summer. In this case Mr. Tricker informed me that 

 the bottom of the pond had been dug over each spring. Probably the 



