110 THE STORY OF THE PLANTS. 



But it is not often in the threefold flowers that 

 we get the calyx green and the corolla coloured, 

 as in these simple and very early types. Most 

 often in this great group of plants the calyx and 

 corolla are both brightly coloured, and both alike 

 employed as effective advertisements. A good 

 case of this sort is shown in the flowering-rush, 

 a close relation of the arrowhead and the water- 

 plantain, but a more advanced and developed 

 plant than either of them. Here the calyx and 

 corolla, instead of forming two separate rows, 

 are telescoped into one, as it were, and are both 

 rose-coloured. In such cases we speak of the 

 combined calyx and corolla as the perianth (another 

 long word, with which I'm sorry to trouble you). 

 In such perianths, however, even when all the 

 pieces are of the same size and are similarly col- 

 oured, you can see if you look close that three of 

 them are outside and alternate with the others; 

 and these three are really the calyx in disguise, 

 got up as a corolla. (An excellent example of this 

 arrangement is afforded by the common garden 

 tulip.) Inside its six rose-coloured perianth-pieces, 

 the flowering-rush has nine stamens, arranged in 

 three rows of three stamens each. Finally, in the 

 centre, it has six carpels, equally arranged in two 

 rows of three. Here the threefold architectural 

 ground-plan of the flower is very apparent. You 

 may say, in short, that the original scheme of the 

 two great groups is something like this: five 

 sepals, five petals, five stamens, five carpels; or 

 else, three sepals, three petals, three stamens, 

 three carpels. But in any instance there may be 

 two or more such rows of any organ, especially 

 of the stamens ; in any instance certain parts 

 may be reduced in number or entirely suppressed ; 



