1922] BUCHHOLZ—VASCULAR PLANTS 279 
but rather a general indefinite all round fitness. It has already 
been shown, however, how developmental selection sets the same 
task for all the competitors. Likewise artificial selection sets a 
uniform standard of excellence of performance for all participants, 
but a standard which is limited by the-powers of discrimination 
of the breeder. 
By providing a very uniform medium for the competition of 
embryos, pollen tubes, etc., and by forcing rigid elimination, develop- 
mental selection precludes indiscriminate survival. The surviving 
plant may owe its existence to the performance record of its parent 
pollen tube, or it may owe its existence to its own performance 
during embryonic development; but in any event, there are very 
definite measures of some kind of excellence to be lived up to on a 
competitive basis. The surviving individuals constitute a class, 
selected for their superiority among several, among dozens, or 
even among hundreds of other individuals which were destroyed in 
this competition. Developmental selection, therefore, is not open 
to this objection which has been urged against natural selection. 
In the fourth requirement, developmental selection again 
excels, while natural selection is only feebly effective, for the 
defeated individuals are rigidly eliminated in developmental 
selection. The losers in the environmental competition are not 
always destroyed from reproduction; their progeny may only be 
iminished somewhat. Artificial selection also meets this require- 
ment fully. 
In connection with these special features of developmental 
selection, it is interesting to consider some of the objections which 
have been raised against natural selection. One of these concerns 
the chances of death, which have been ably discussed by several 
evolutionists, who point out that the destruction of individuals is 
very indiscriminate, that the fittest do not always survive, for many 
of them are destroyed. Likewise, the least fit do not always perish. 
Thus it has been urged that there is little evidence that natural 
selection actually selects any specific class of individuals in prefer- 
ence to others. In fact, so complex is the environment in which 
natural selection must sort out the superior, that accident and 
chance really play a major rdle. 
