126 THE TEACHING BOTANIST 



rapidly that even the best of books are soon superseded 

 unless kept up with advances by new editions. 



Upon structural botany (i.e. external anatomy) the 

 work of undisputed preeminence is Gray's " Structural 

 Botany," a very clearly written and well-illustrated 

 work ; and in condensed form the same merits prevail 

 in his " Elements of Botany." The morphology of 

 these works, however, is not modern in spirit, but of a 

 formal sort, largely laid aside by modern investigation. 

 On morphology the most authoritative work is Goebel's 

 " Organographie der Pflanzen," now appearing in parts, 

 a work for which there is no equivalent in English, and 

 which, it is to be hoped, will soon be translated. There 

 is really at present no work in English giving the 

 results of modern studies on the morphology of the 

 higher plants, though several of the text-books men- 

 tioned later contain it in part. 



In physiology we may distinguish two classes of 

 works, those giving practical directions for experimen- 

 tation and the general hand-books or text-books. Of 

 the former, MacDougal's " Experimental Plant Physi- 

 ology " is one of the simplest and most practical works. 

 Darwin and Acton's " Practical Physiology of Plants ' 

 (second edition) is most excellent and suggestive, while 

 Detmer's widely used work, translated into English 

 by Moor as " Practical Plant Physiology," combines a 

 practical laboratory guide with a good text-book of the 

 subject. Of general works on plant physiology, the 



