80 The Waterlilies. 



and the larger in N. elegans, and Eichler (1878, 2 : 183-186) records both 

 numbers for N. alba. A trimerous flower of N. atnpla was the type of 

 Gaudichaud's N. trisepala. Hexamerous and heptamerous flowers are 

 known. When five sepals occur, two stand in place of one in the 

 posterior position ; when only three are present, the posterior one is 

 lacking (Payer, 1857 ; Eichler, 1. c). 



The number of petals varies from 7 (A 7 ", tetragona) to 33 (Al. capensis). 

 The 4 outermost are largest and alternate with the sepals ; over each 

 interval between these, i. e., opposite each sepal, is a pair of smaller 

 petals, making a whorl of 8. This seems to be followed in Brachyceras 

 and Lotos by another alternating whorl of 8. Of this row usually only 4 

 or 5 are present in N. caerulea, while an additional row is found more or 

 less complete in N. capensis and zanzibariensis. In 

 Hydrocallis the petals are all regularly arranged in 

 alternating whorls of 4. Here, also, the outermost 

 stamens follow in one or two whorls of 4 ; then come 

 one or two whorls of 8, the first of which has two 

 members over each interspace between the preceding 4; 

 within this it is impossible to make out any order. 

 fio. .-Fiorai diagram The stamens of the Lotos group follow on in more or 

 forNymphaea. j egs definite w horls of 8, and the same may frequently 



be seen in Brachyceras. In old flowers of N. caerulea, long after in- 

 florescence, when the organs are spread apart by the growth of the 

 ripening ovary, I have several times found the stamens arranged in 16 

 vertical lines, with mostly 4 stamens in each line. The whorled arrange- 

 ment is not distinct in Castalia, and Eichler (1. c.) states for A^. alba 

 that there are 4 petals alternate with the sepals, and 4 alternate with 

 these, i. e., over the sepals. These 8 are the beginning points for 

 oblique lines of successively smaller petals, rising right and left with 

 equal inclination. Each series has, on the average, four members. The 

 inclination of the spirals is such that each successive petal stands over 

 the space between two neighbors, so that in all 16 vertical rows of 2 

 petals each are formed. The arrangement of the stamens was not made 

 out. The inner petals and stamens are inserted at various levels up the 

 sides of the ovary (receptacle). There is a narrow, naked zone between 

 the petals and stamens in Lotos and Anecphya, but in other genera the 

 two sets of organs are in continuous series, except in some forms of N. 

 Candida and tetragona. The carpels are always in a circle in the middle 

 of the flower, abutting against a central prolongation of the floral axis. 



