THE LANGUAGE OF BOTANISTS. 3 



conditions of life, and enables us to discover what gave rise to migrations and 

 caused the redistribution of floras. These phenomena are the subject-matter of 

 the History of the Plant World in the fullest meaning of the phrase; and their 

 explanation is eagerly sought by modern botanists. 



In 1853 Unger, to whom all branches of Botany were equally familiar, made 

 the first attempt at such a history of plants. Since then a great number of new 

 discoveries have been made both in the Old World and the New. Men with minds 

 intent upon this object are everywhere searching for the fossil remains which 

 throw such valuable light upon it; but, so far, this — the most recent branch of 

 Botany — has not led to a comprehensive result. We find ourselves, as it were, in 

 the midst of a stream in full flood owing to the number and magnitude of its 

 tributaries, and it is no easy matter to steer clear of shoals and run safely into 

 harbour. Some decades hence it may perhaps be possible to write an accurate and 

 complete history of the plant world founded upon the mass of authentic evidence 

 which will by that time have been winnowed from the records of past ages. At 

 present I must content myself with sketching in general, and often ill-defined, 

 outline the changes which take place in the world of plants. 



The foregoing introductory remarks concerning the sources from which materials 

 for a history of plants are derived serve also to explain the arrangement of the 

 subject-matter to be dealt with in the Second Volume of this work. The order of 

 presentation of the different parts of the subject will follow the stages of develop- 

 ment of the science. A history of the entire plant-world considered as a single 

 great community must be preceded by a history of species. But each species is 

 the sum of numberless individuals, which are alike in constitution and have the 

 same external characteristics, and a history of species therefore presupposes a 

 knowledge of the history of the individual. Accordingly, our first business is 

 to describe the rejuvenescence, multiplication, and distribution of individuals, and 

 to show by what means a plant, considered as a separate organism, maintains 

 itself, takes possession of its habitat, and is enabled to keep its hold on that 

 habitat up to the moment when it is replaced by descendants endowed with a 

 vitality of their own. 



THE LANGUAGE OF BOTANISTS. 



Before entering upon a description of any of the above phenomena, I feel it 

 necessary to say a few words respecting the technical botanical terms of which 1 

 shall make use. The need of short and compendious names to denote particular 

 forms, particular organs, and particular processes, has been always universally 

 recognized, and more or less appropriate additions to our vocabulary have been 

 made by men of science from time to time. As might be expected, these designa- 

 tions are not only an expression of the particular standpoint to which, at the time 

 of their invention, the actual knowledge of plant-life had most recently attained; 

 but they are also liable to bear the stamp of theories advanced by eminent 



