42 



The Waterlilies. 



long at its summit. This is followed by a second internode, much shorter, 

 0.3 to 1.3 cm. long, and this bears the tuft of leaves and roots which are 

 the beginning of a new plant. If these shoots are detached, other shoots 

 develop, and so on almost indefinitely, even from a tuber no bigger than 

 the end of one's thumb. 



Phyllotaxy in the Nymphaeas presents some peculiarities. As might 

 be expected, forms with elongated rhizomes (Eu-castalia) have the simpler 

 orders of leaf arrangement, and where dorso-ventrality appears leaf scars 

 are only half as numerous on the lower as on the upper side. In N. 

 tuberosa and odorata, the phyllotaxy seems to be as low as f or f, and 

 the internodes are 1.3 cm. or more long. N. alba shows a much higher 

 order, probably /r or \\ (Raciborski 1894). But the erect tuberous 



stems are so densely crowded with 

 leaf attachments as to leave only 

 narrow, sinuous lines of stem-sur- 

 face visible ; the order of the spirals 

 I have not determined. 



One can speak of a definite 

 anthotaxy also in the genus Nym- 

 phaea, since a plant once in flower 

 produces its bloom continuously 

 until it dies. In N. gigantea the 

 peduncular attachments form sepa- 

 rate and distinct secondary spirals 

 alternating with two parallel spirals of leaves (Caspary, 1865). In other 

 species the flowers occur in the place of leaves, as members of the 

 leaf-spirals. In every case the peduncles arise entirely independently 

 of any leaf axil and there is no visible trace of a bract. The relation 

 of leaves and flowers in the primary leaf-spirals is shown in the following 

 series taken from Raciborski (1894). The numbers represent leaves, 

 the letter f stands for a flower. A rhizome of A^. alba taken up in 

 autumn gave 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, f, 12, 13, f, 14, 15, f, 16, 

 17, f, 18, 19, f, 20, 21, f, 22, 23, 24, 25, 26, 27, 



3 2 > 33- f . 34. 35. 36, 37. 38, 39, 40, 41. 42, 43. f. 



48, 49, f, 50, 51, f, 52, 53, f, 54, 55, f, 56, 57, f, 



62, 6$, f, 64, &c. ; the flowers up to 45 have already bloomed, the others 



would come out the next season. In N. zanzibariensis, a very floriferous 



species, leaf and flower alternate regularly after the plant once begins to 



bloom. " N. stellata" gave 1, 2, f, 3, 4, 5, f, 6, 7, 8, f, 9, 10, 11, f, 



Fig. 15. Perennating body of N. mexieana. Seen 

 from nearly opposite sides. Natural size. 



28, 29, f, 30, 31, f, 



44, 45, f, 46, 47, f, 

 58, 59, f, 60, 61, f, 



