4 Introduction. 



were proposed as to the nature of plants, their organisation or 

 mutual relations ; the only point of interest was the knowledge 

 of individual forms and of their medicinal virtues. 



The descriptions were at first extremely inartistic and un- 

 methodical ; but the effort to make them as exact and clear as 

 was possible led from time to time to perceptions of truth, that 

 came unsought and lay far removed from the object originally 

 in view. It was remarked that many of the plants which 

 Dioscorides had described in his Materia Medica do not 

 grow wild in Germany, France, Spain, and England, and that 

 conversely very many plants grow in these countries, which 

 were evidently unknown to the ancient writers ; it became 

 apparent at the same time that many plants have points of 

 resemblance to one another, which have nothing to do with 

 their medicinal powers or with their importance to agriculture 

 and the arts. In the effort to promote the knowledge of plants 

 for practical purposes by careful description of individual forms, 

 the impression forced itself on the mind of the observer, that 

 there are various natural groups of plants which have a distinct 

 resemblance to one another in form and in other characteristics. 

 It was seen that there were other natural alliances in the veget- 

 able world, beside the three great divisions of trees, shrubs, and 

 herbs adopted by Aristotle and Theophrastus. The first per- 

 ception of natural groups is to be found in Bock, and later 

 herbals show that the natural connection between such plants 

 as occur together in the groups of Fungi, Mosses, Ferns, 

 Coniferae, Umbelliferae, Compositae, Labiatae, Papilionaceae 

 was distinctly felt, though it was by no means clearly understood 

 how this connection was actually expressed ; the fact of natural 

 affinity presented itself unsought as an incidental and indefinite 

 impression, to which no great value was at first attached. The 

 recognition of these groups required no antecedent philosophic 

 reflection or conscious attempt to classify the objects in the 

 vegetable world ; they present themselves to the unprejudiced 

 eye as naturally as do the groups of mammals, birds, reptiles, 



