92 



PLAN OF THE FLOWER. 



[LESSON 13. 



the fifth, needed to complete the symmetry, being left out. And 

 the Monkshood (Fig. 185, 186) has five very dissimilar sepals, 



and a corolla of only two, very small, 

 curiously-shaped petals ; the three need- 

 ed to make up the symmetry being left 

 out. For a flower which is unsymmet- 

 rical but regular, we may take the com- 

 mon Purslane, which has a calyx of 

 only two sepals, but a corolla of five 

 petals, from seven to twelve stamens, 

 and about six styles. The Mustard, 

 and all flowers of that family, are un- 

 symmetrical as to the stamens, these 

 being six in number (Fig. 188, while 

 the leaves of the blossom (sepals and 

 petals) are each only four 

 (Fig. 187). Here the 

 stamens are irregular also, 

 two of them being shorter 

 than the other four. 



246. Numerical Plan of 

 tlrc Flower, Although not 



easy to make out in all 

 cases, yet generally it is 

 plain to see that each 



blossom is based upon a particular number, which 

 runs through all or most of its parts. And a prin- 

 cipal thing which a botanist notices when examin- 

 ing a flower is its numerical plan. It is upon this 

 that the symmetry of the blossom depends. Our two 

 pattern flowers, the Stonecrop (Fig. 168) and the 

 Flax (Fig. 174), are based upon the number five, 

 which is exhibited in all their parts. Some flowers of this same 

 Stonecrop have their parts in fours, and then that number runs 

 throughout ; namely, there are four sepals, four petals, eight stamens 

 (two sets), and four pistils. The Mustard (Fig. 187, 188), Radish, 



FIG. 185. Flower of a Monkshood. 186. Its parts displayed : the five larger pieces are the 

 sepals ; the two small ones under the hood are petals ; the stamens and pistils are in the 

 centre. 



FIG. 187. Flower of Mustard. 188. Its stamens and pistil separate and enlarged. 



