28 



JOUKNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



perceived that the conception of evolution was the direct outcome of 

 such study of geographical botany. 



Now let us turn to the latest exponent of ecology, De. Schimper, in 

 his " Plant-Geography upon a Physiological Basis " (1903). 



The objects of Geographical Botany, he tells us, have hitherto been 

 the delimitation of separate floral districts ; but this is only the founda- 

 tion of the science. " The essential aim of Geographical Botany is 

 an inquiry into the causes of differences existing among the various 

 floras." "A transformation, always continuous, is wrought by the 

 reciprocal action of the innate variability of plants and of the variability 

 of external factors. Experience shows that morphological differentia- 

 tions are profoundly and rapidly modified by changes in the environ- 

 ment every one of which immediately involves a change in the organi- 

 zation of plants. ... It is by adaptations that the causes of the 

 differences in the facies of the vegetation . . . are rendered more com- 

 prehensible; so that their investigation is to be numbered among the 

 chief duties of Geographical Botany." But all this is synonymous 

 with the search for the origin of species, which Schimper, like Darwin, 

 proves to be the result of adaptation to changed conditions of life, 

 through the variability of the living organism. Such was the outcome 

 of Darwin's studies of plants and animals in his tour round the world. 

 Dr. Warming, M. Costantin, many Americans, and others have come 

 to the same conclusion."^ 



A point worth emphasizing is that Dr. Weismann insists on the 

 direct action of changed conditions of life, so acting on the soma of an 

 organism, that the effect to be hereditary must have influenced the 

 reproductive organs. He seems, therefore, to mean that the organism 

 acted upon must be an adult. 



Darwin, however, uses the words italicized above solely for off- 

 spring ; as e.g. seeds sown in a new and very different locality. Then, 

 any changes of structure take place between the germination and the 

 adult stage. For it is not till flowers (metamorphosed somatic organs) 

 appear after the vegetative stage is completed, that the effect upon 

 the soma may or may not be hereditary. 



We may hypothetically suppose that the protoplasmic continuity 

 from cell to cell may be the mechanism for passing on the influence 

 from the soma to the ovule. But that such a result is somehow pro- 

 cured is to be seen everywhere. 



Let us now turn to the " Foundations of the Origin of Species," 

 written in 1842. 



Dr. F. Darwin traces the conception of evolution in his father's 

 mind from some period during his voyage, starting apparently with his 

 reflections on the Pampian fossils of South America and the flora and 

 fauna of the Galapagos Archipelago, situated some six hundred miles 

 from the west coast of South America. He quotes as follows from his 

 father's note-book 1837-8 (that was before he had read Malthus's 



* 111 the above quotation the italics are mine. 



