91G REPORT— 1900. 



Section K.— BOTANY. 

 Pkesidest of the Sectiox — Professor Sxdjiet H. Vines, M.A., D.Sc, F.R.S. 



THURSDAY, SEPTEMBER 6. 



In the absence of tlie President the following Address was read by Dr. D. II. 

 ScoTX, F.R.S. :— 



There has been considerable difference of opinion as to whether the present year 

 marks the close of the nineteenth or the beginning of the twentieth century. But 

 whatever may be the right or the wrong of this vexed question, the fact that 

 the year-date now begins with 19, instead of with 18, suggests the appropriate- 

 ness of devoting an occasion such as the present to a review of the century which 

 has closed, as some will have it, or, In the opinion of others, is about to close. I 

 therefore propose to address you upon the progress of Botany during the nineteenth 

 century. 



I am fully conscious of the magnitude of the task which I am undertaking, 

 more especially in its relation to the limits of time and space at my disposal. So 

 eventful has the period been that to give in any detail an account of what has 

 been accomplished during the last hundred years would mean to write the larger 

 half of the entire history of Botany. This being so, it might appear almost 

 hopeless to attempt to deal with so large a subject in a Presidential Address. But 

 I trust that the very restrictions under which I labour may prove to be rather 

 advantageous than otherwise, inasmuch as they compel me to confine attention 

 to what is of primary importance, and thus to give special prominence to the main 

 lines along which the development of the science has proceeded. 



Statistics. 



"We may well begin with what is, after all, the most fundamental matter, viz., 

 the relative" numbers of known species of plants at the beginning and at the end of 

 the century. It might ai^pear tliat the statistics of plants was a subject susceptible 

 of very simple treatment, but unfortunately this is not the case. It must be 

 remembered that a 'species' is not an iu variable standard unit, like a pound 

 or a pint, but that it is an Idea depenrlent upon the subjectivity of individual 

 botanists. For Instance, one botanist may regard a certain number of similar 

 plants as all belonging to a single species, whilst another maj' find the differences 

 among them such as to warrant the distinction of as many species as there are 

 plants. It is this Inevitable variation in the estimation of specific characters which 

 renders it difficult to deal satisfactorily with plants from the statistical point of 

 view. However, the following figures may be regarded as giving a fair Idea of 

 the increase in the number of ' good ' species of living plants. 



It la generally stated that about 10,000 species of plants were known to 

 Ijlnnseus in the latter half of the eighteenth century, of which about one-tenth 

 were Cryptogams ; but so rapid was the progress in the study of new plants at 

 that time that the first enumeration of plants published In the nineteenth century, 



