HOW FLOWERS CLUB TOGETHER. 147 



what we call " a double flower " in a rose, a but- 

 tercup, or any other simple blossom is one in 

 which the stamens have been converted into super- 

 numerary and useless petals; while in a composite 

 it is a flower-head in which the central florets 

 have been converted into barren ray-florets. In 

 either case, however, the result is the same — the 

 flowers are rendered abortive and sterile. 



Nature's way is quite different. Here is how 

 she manages the fertilisation of one of these ray- 

 bearing composites — say for example the sun- 

 flower, where the individual florets are quite big 

 enough to enable one to follow the process with 

 the naked eye. The large yellow rays act as ad- 

 vertisements ; the bee, attracted by them, settles 

 on the outer edge and fertilises the flowers from 

 without inward. To meet this habit of his, the 

 florets of the sunflower pass through four regu- 

 lar stages. They open from without inward. In 

 the centre are unopened buds. Next come open 

 flowers, in which the stamens are shedding their 

 pollen, while the stigmas are still hidden within 

 the tube. Third in order, we get florets in which 

 the stamens have withered, while the stigmas have 

 now ripened and opened. Last of all, we get, 

 next to the rays, a set of overblown florets, en- 

 gaged in maturing their fertilised fruits. The 

 bee thus comes first to the florets in the female 

 stage, which he fertilises with pollen from the 

 last plant he visited ; he then goes on to florets 

 in the male stage, where he collects more pollen 

 for the next plant to which he chooses to devote 

 his attention. The florets of the sunflower are 

 interesting also for the fact that, unlike most 

 composites, they still retain obvious traces of a 

 true calyx. 



