WATER LILY. 57 
appendage, and that at the end of the sepal. This 
shows how gradual in some cases, is the passage of a 
leafy organ to another form. But in the Wallflower, 
and Stock, there is no such gradual passage from the 
condition of leaf to that of sepals; yet these partake 
quite as much of the leafy character, as do the sepals 
of the Rose. The bud of the Peony gives a similar 
illustration as the Rosebud. 
92. The petals also partake of the nature of leaves, 
although from the variety of their colours they are not 
likely to be so considered by the generality of observers. 
There are, however, many facts which establish this 
point. In the flower of the Lily (pl. 14. f. 9.), the 
outer row (¢) of the perianth (par. 58.) will be found 
to be marked with green on the back, which is not the 
case with the inner; and yet there is no other difference 
in the nature of these organs. A still more striking 
proof is offered in the flower of the white Water Lily 
(pl. 19. f. 4.), in which the calyx consists of four sepals 
(s.), which are tinged with green on the outside, but 
are white inside (f. 5.). The petals (f. 6.) next to the 
sepals are white, and nearly of the same form; while 
those situated more towards the centre of the flower 
will be found to become smaller and smaller by degrees, 
and to change their colour from white to yellow, while 
at the same time the tips of these changing petals 
(f 7.) will be found to be furnished with a small yellow 
thickening, which gradually assumes a larger size as 
the petal is placed still nearer the centre of the flower, 
till at length it becomes difficult to determine what is 
a petal, and what a stamen (f. 8.). There is, in fact, in 
