HISTORY OF CLASSIFICATION 
7 
of Plants. Genera Plantarum, of Bentham and Hooker which was issued 
from 1862 to 1883. George Bentham is undoubtedly in certain qualities 
of acuteness of intellect and in analytical power the premier of all plant 
systematists. Joseph Hooker was in range of his mind and wide and 
progressive grasp of problems the great botanical intellect of the Nine¬ 
teenth Century. Of all systematic works the Genera Plantarum is at 
once the most thorough, the most even, the most complete, bearing evi¬ 
dences of the most profound discernment, the soundest judgment, the 
most scholarly finish. It has had a vast influence on the progress of 
systematic botany, since no other work equals it in the excellence of 
its taxonomic judgments and in the precision which is given to families 
and genera. And yet in regard to it one must make a most extraordinary 
statement. Brought out at a time when the whole scientific world was 
stirred by the ferment of the evolutionary theory, it contains no hint of 
ideas of phylogeny or of progressive differentiation. 
This amazing fact can only be explained in one way. Bentham was 
much the elder of the two men and he undoubtedly dominated the work 
in this particular. The mold of his mind had been cast before the 
epochal period of Charles Darwin and he did not respond in this par¬ 
ticular to the thundering call of a new day. Joseph Hooker on the other 
hand, the younger man, was a pronounced evolutionist, the friend and 
confidant of Darwin, a man to whom Darwin unfolded his problems, his 
plans, his hundreds of detailed queries, for advice and assistance in re¬ 
gard to the plant world. 
The Genera Plantarum is therefore cold and inflexible; it is in its spirit 
rather a treatise on mathematics than a work dealing with the field of 
life. There is lacking in it the expression of all theories of phylogeny 
or heredity or variation. A century before, Bernard de Jussieu, in the 
Tardin des Plantes at Paris, worked out in his flower beds the beginnings 
of a natural system, but he refused to publish a theory concerning it. 
It may be that he was right, that his results developed farther, carried 
farther, as being freed from the chains of theory. It is possible that in 
the end Bentham and Hooker may be equally justified. 
I now return to the beginning of the Nineteenth Century to consider 
the work of four men, Robert Brown, Wilhelm Hofmeister, Stephen 
Endlicher and Charles Darwin, as furnishing the foundation for the 
great work of Engler and Prantl, Die Naturlichen Pflanzenfamilien, put 
forth within the last 30 years. Robert Brown discovered that the ovules 
of certain conifers were naked and established gymnospermy as one of 
the most remarkable facts in the plant world, especially as it led on to 
important researches by other botanists. The Gymnosperms were thus 
segregated from Dicotyledons and later established as a distinct coordi¬ 
nate class. Alexander yon Humboldt called Robert Brown easily the 
first of botanists. He distinguished in his monographs more clearly 
than had ever been done before between morphological characters of 
systematic value and physiological adaptations, but he promulgated no 
theory of classification and proposed no system, and yet he is considered 
one of the profoundest botanists. Hofmeister worked out the life-cycles 
and antithetic alternation of generations which occur in liverworts, 
