220 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



THE EEV. PEOFESSOE J. S. HENSLOW AS ECOLOGIST. 



By Eev. Professor G. PIenslow, M.A., V.M.H., &c. 

 [Read June 18, 1912; Sir J. T. D. Llewelyn, Bt., V.M.H., in the Chair.] 



My father was born in 1796, and died in 1861. As a boy he was 

 encouraged to be interested in Nature by both his father and mother, 

 who were fond of natural history ; and especially by a Mr. Samuel, an 

 assistant master in the school at Oamberwell. 



When an undergraduate at Cambridge he studied chemistry and 

 mineralogy; and he was elected professor of the latter science in 1822. 

 On the death of Professor Maetyn he was elected Professor of Botany 

 in 1827. 



After acquiring a familiarity with the British flora, he found he had 

 no special taste for systematic botany. The study of plant-structure, 

 solely for the sake of classification, did not appeal to him; but of 

 geographical botany he was an ardent student. In a notebook in my 

 possession he has epitomized a number of works by different writers, 

 beginning with M. A. P. de Candolle's article on Giogmphie 

 Botanique."^ That botanist was the first truly scientific exponent of 

 what is now called " Ecology "; for in that work he considers all the 

 influences of the environment, or what Darwin called the " Direct 

 action of the conditions of life." These are light, heat, moisture, soil, 

 &c., which act upon plants. It is they which account for the distribu- 

 tion of plants. He describes the formations of *' Stations," a word 

 adopted from Linnaeus. The study of these was *' topography." We 

 see an allusion to the struggle for existence, if not to " natural selec- 

 tion," in the sentence, "All plants of the same country hold civil 

 war," and De Oandolle describes a number of conditions which 

 favour some species more than others; adding that with two species 

 struggling together in different places, the results may be reversed. 

 Thus " Carex arenaria in sand chokes those which in clay choke it." 

 Such results should be described as the survival of the fittest under 

 the circumstances. 



In my father's notes on Humboldt's Tableaux de la Nature and 

 Essai sur la Geographie, he quotes that author's words: — Botanists 

 generally limit their researches to descriptive botany, but geographical 

 botany is not less important." He observes himself: — Botanists 

 would rather receive one of our most common weeds from a newly- 

 discovered or newly-explored country, than a new species of an 

 already known genus. There are higher departments of botany than 

 mere collectors of specimens are aware of. For, to ascertain the 

 geographical distribution of a well-known species is a point of vastly 

 superior interest to the mere acquisition of a rare specimen." 



* Dictionnaire des Sciences naturelles, Tome xxviii, p. 359, 1820. 



