162 The Anatomy of Plants BOOKII 



great memoir, Das mechanische Prinzip im anat. Ban d. 

 Monocotylen, Leipzig (1874), in which he showed how 

 admirably the skeleton of the plant is adjusted to its 

 relations with the varied features of the environment. The 

 same idea was elaborated and amplified in Haberlandt's 

 Physiologische Pflanzenanatomie of 1884, in which the tissues 

 were examined and classified from the same point of view. 

 Another work which treated of anatomical structure 

 from the same standpoint was Tschirch's Angewandte 

 Pflanzenanatomie, published in 1888. 



Though such a treatment of the anatomy of plants 

 cannot in any sense supersede the more strictly scientific 

 classification based on morphology and phylogenetic rela- 

 tions, it affords a valuable supplement to it, and brings 

 prominently forward the relationship between the life of 

 the organism and the structures which minister to it, and 

 indeed render it possible. 



A fourth line of research, having a more direct bearing 

 on the principles of taxonomy, was initiated early in the 

 period under review by Duval-Jouve and continued by 

 him for several years. It was based upon the old idea, 

 propounded somewhat obscurely long before by Linnaeus 

 and by de Candolle, that anatomical structure may be 

 employed for diagnostic purposes in determining systematic 

 relationship. The germ of the idea may be seen indeed in 

 the names Exogens and Endogens employed by de Candolle 

 as alternatives for Dicotyledons and Monocotyledons, and 

 in the subsequent writings of Endlicher, Lindley, and 

 others. Duval-Jouve was followed by Bureau in 1872, 

 Bertrand in 1874, Engler in 1874 all of whom showed a 

 direct connexion between anatomical structure and generic 

 relations in various groups of plants. The founder of the 

 method as one of general application, however, was Radlkof er, 

 who gave a new impetus to it in his great monograph 

 of the Sapindaceous genus Serjania, published in 1875. 



