THOSE who have closely followed the controversy 

 respecting the various theories of Heredity will not 

 have failed to notice that apart from a large portion of 

 the work on the Mendelian theory most of the writers 

 have been professional zoologists and most of their views 

 have been founded on the behaviour of animals. The 

 Rev. Professor Henslow in his book (The Heredity of 

 Acquired Characters in Plants. London: John Murray. 

 1908. Price 6s. net) alludes to this fact and insists that 

 the study of plants leads to a totally different conclusion 

 from that arrived at by many who have devoted their 

 attention to the animal kingdom. More especially he 

 insists upon the need for ecological study of plants if the 

 problem of heredity is to be properly attacked. 



Now the ecologist studies " plants at home " and not 

 with any idea of classification, " but solely for the sake 

 of their physiological peculiarities connected with habit 

 of growth and evolution." (p. 45.) 



And as a result of this study he " groups plants into 

 ' associations ' according to their environments, and calls 

 plants of dry districts xerophytes; of moist, marshy 

 places, hygrophytes; true aquatic plants being hydro- 

 phytes, and all of an intermediate character, meso- 

 phytes." (p. 24.) Then he proceeds to his second step, 

 which is to ascertain how these plants came to acquire 

 the adaptive structures which enable them to exist under 

 such very different conditions as we know that plants 

 are capable of existing under. The author's reply to this 

 question may be found in the following passages. 



The origin of Variations in Structure (upon which alone species 

 are based) is due to an inherent Power within the Plant, by means 

 of which it Responds to the Direct Action of changed conditions 

 of Life. (p. 6.) 



And again 



