146 TILLEES OF THE GKOUND CHAP. 



a tremendous number of improvements have been 

 made. 



To understand this new method we must go 

 back a little. We have already seen how the 

 Assyrians and the Arabs carried the pollen-bearing 

 branches of the date-palm to the fruit-bearing 

 trees, even though they did not understand clearly 

 the meaning of pollen. The idea of taking away 

 the stamens, or little threads, the swollen tops 

 of which produce the pollen, from a flower which 

 has both stamens and seed-pods, and bringing to it 

 instead pollen from another flower, was much less 

 likely to occur to people ignorant of botany, but 

 yet we have reason to believe that this was done 

 by the Japanese and Chinese very early, and was 

 also to some extent done by the Eomans. When 

 this is done, and when afterwards the seed sets, 

 this seed may grow into plants different from both 

 parents. Very often 'also the seedlings differ a 

 great deal among each other. This crossing, as it 

 is called, is then a way of producing a number of 

 varieties in cultivated plants. 



In the seventeenth century gardeners in Europe, 

 and especially in Holland, began to cultivate tulips 

 and auriculas, and to produce all sorts of varieties. 

 If we had time we might tell all sorts of curious 

 stories about the tulip mania how tulip bulbs 

 were sold for their weight in gold ; how men 



