138 HISTORY OF BOTANY 



disappear and the plant world is revealed as a great tree, 

 its roots buried among the primeval unicellular forms 

 of the remotest past, the tips of the loftiest twigs the 

 living plants of the present, some tracing their descent 

 almost from the original stock, others springing out at 

 different levels from the main trunk or from its lateral 

 branches, others still, and these the most prominent 

 though at the same time the most recent, arising in 

 dense tufts from the topmost branches, like the luxuriant 

 outgrowths at the apex of a pollarded willow. Here 

 then was opened up for the taxonomist a field of labour 

 of boundless extent, but the unravelling of the maze 

 was not a task that could be accomplished at once or by 

 any single man. 



Let me attempt, first of all, to give you a summary 

 of the general situation in botanical science just after 

 the publication of the Origin and before the new leaven 

 had begun to make its influence felt on the various depart- 

 ments into which our science had now become divided. 



For many years after 1859 we meet with attempts 

 to sketch out the phylogeny of special groups, but no 

 comprehensive effort to produce an entirely new taxo- 

 nomic scheme on genealogical lines. Up to 1860 there 

 was nothing better available than the Candollean system, 

 which indeed maintained its ascendancy for over half a 

 century more. 



In morphology the views of Wolff, who regarded 

 " all parts of the plant except the stem as modified 

 leaves/' and of Goethe, as extended by Alexander Braun, 

 who considered all leaves as modifications of an ideal 

 leaf, were not productive of any. very clear insight into 

 the architecture of the plant as a whole. The conception 

 of the flower was based on the idea of a progressive 

 metamorphosis of the appendages of the floral axis from 

 the foliage leaf through the bract to the sepal, petal, 

 stamen, and carpel, so that the flower was regarded as a 

 greatly modified vegetative shoot. 



