No. 496] ASPECTS OF THE SPECIES QUESTION 



251 



would be so nearly alike as to be in themselves inade- 

 quate for the separation of the two by ordinary taxonomic 

 methods. These facts, which have been illustrated more 

 than once in my own cultures, are quite at variance with 

 the supposition that closely related forms are most alike 

 in the seedling and younger stages and most divergent 

 in the members of the adult formed latest. 



Another form of transgressive variability is found 

 when some descendants of individuals belonging to strain 

 A, are apparently but little separated from B. Morpho- 

 logically this would appear as an intergradation, but in 

 reality the resembling individuals are divided and 

 divisible into two groups, each carrying its own inherited 

 potentialities, and in their progeny arranging themselves 

 more or less symmetrically around the form of the strain, 

 race or species. That the inclusion of the two is widely 

 different may be illustrated in a striking manner by 

 their action when crossed by a third form. 



It can not be maintained that taxonomic thought has 

 accurately or quickly reflected these modern estimations 

 of the nature of living forms, for the very ma-nitude 

 of the system necessary for the expression of relation- 

 ships operates to prevent anything like a rapid or ac- 

 curate adjustment. 



Taxonomy is an eminently practical phase of botany, 

 and it may reach its greatest general and total usefulness 

 by confining its practise to the delineation of readily ap- 

 preciable entities whether thev be ''natural" or "arti- 

 ficial." 



So far as investigation in genetics and in the general 

 functional activities of plants is concerned, however, 

 progress is to be made only by increasing precision of 

 measurement, and refined exactness of method of estima- 



but slowly. There are writers who still insist that the 

 intricate pattern woven by the plant during its ontogeny, 



