332 



GENERAL BIOLOGY 



multiplied ; the new ones growing up are separated parts of 

 that one, and are therefore essentially like it. 



The parts, however, are not necessarily identical with the 

 parent, or with each other; when separated they may 

 develop slight differences, as in the well known phenomenon 

 of bud variation, and such differences may be increased 



FIG. 186. Duckweed (Spirodela polyrhiza). The growth from a 

 "* - single plant in twelve days. Photo and culture by L. S. Hawkins. 

 * Note the grouping in pairs, with small lobes^ forming between the 

 larger old ones of the dividing individuals. 



artificially by selection. One branch of a rose bush may 

 develop finer flowers than any other on the bush. Cuttings 

 of this branch may be selected for growing, and the best- 

 flowered shoots developing from these cuttings may be 

 again selected with some advantage. But there is no 

 probability that these improvements would be inherited. 



