340 THE STRUCTURE OF FLOWERS. 



of wliich some of tlie members have already differentiated 

 into carpellary, others into staminal organs, the outer 

 appendages being simply bracts, like, we will say, those 

 surrounding the stamens or ovule of the Yew. 



As insects often come for pollen alone — as in honeyless 

 flowers of Laburnum, Poppies, St. John's Wort, and Roses, — 

 and then pierce the juicy tissues for moistening the honey, as 

 they have been seen to do in Anemone, Laburnum, Hyacinths, 

 Orchis, etc., we may, I think, infer with some probability 

 that they did the same with the primitive flowers. 



Having once attracted insects to come regularly, then a 

 multitudinous series of differentiations would follow. The 

 corolla would in all probability be the first to issue out of the 

 bracts, as being the next whorl to the stamens and as a 

 result of stimulus ; other changes, already described under 

 the Principles of Variation, would follow by degrees and in 

 different combinations ; but in every case they would be due 

 to the responsive action of the protoplasm in consequence of 

 the irritations set up by the weights, pressures, thrusts, 

 tensions, etc., of the insect visitors. 



Thus, then, do I believe that the whole Floral World has 

 arisen. 



