100 Muhlenbergia, Volume 4 
significance given to the word variation. Lamarck, in his 
strong feeling for adaptation, hit upon the two essential facts, en- 
vironment and variation, but his application for these criteria 
was purely academic.” 
‘De Vriese has taken the first definite step in advance by 
the use of experiment to determine a species. It remains to be 
seen whether his concept of elementary species will clarify or 
confuse. It can not be accepted even provisionally until much 
more experimental work has been done.” 
“In the last decade or two, conservative American botanists 
have often expressed the view that proper specific characters can 
be drawn only from the flower and fruit, or from the reproduc- 
tive parts, whatever they may be. Since this has sometimes 
been said to have been Dr. Gray’s view also, it seemed that it 
would be both profitable and interesting to compare the criteria 
of conservative and radical describers of species in the same fam- 
ily and genus. ‘Time was lacking for a thorough and complete 
comparison, but in the few families selected the results seem 
representative. It was quickly seen that many current species 
accepted by all were not based upon reproductive characters, 
and that some of the most doubtful were. It further appeared 
that while habit, leaf, stem, etc., played slightly more important 
parts in later work, there was little essential difference in the 
kind of criteria used. The striking difference lay in the fact 
that the new species segregated are based upon much smaller 
variations of the parts concerned, as a rule, and are consequently 
much more difficult to distinguish when represented by many 
individuals.” 
(Zo be concluded in the next number.) 
