76 



Reviews of Foreign Literature. 



Ucber Anlage luid Aiisbildimg von Libriformfdsern in Abhangig- 



keit von ausseren VerJialtnissen. 



This article, which is reviewed in the Botanische Centralblatt, 

 appeared in the Botanische Zeitung some time ago. The qucs- 

 tion considered is, how far the origin and development of plant 

 tissues are dependent on outward surroundings, particularly the 

 changes which occur in the xylem, the origin and growth of the 

 libriform and its accompanying cells. In other words, the author 

 has tried to prove that the anatomical structure of the plant, as 

 well as its morphological characteristics, depends largely on its 



environment. 



The plants experimented upon were Urtica dioica, Robinia 

 Pseudacacia^ Quercns sessiliflora and Ricimis communis. Dwarf 

 plants of Urtica were cultivated in small pots, others of the same 

 species were grown in water in which were dissolved the salts 

 adapted to them with the exception of phosphates. The results 

 showed that the plants cultivated in pots with a comparatively 

 small supply of water, developed a much larger libriform zone 

 and a correspondingly smaller parenchymatic zone than those of 

 the water culture. In order to prove that the lack of phosphates 

 had nothing to do with this difference in tlie xylem, examples of 

 Robinia Pseiidacacia and Qucrcus sessiliflora were cultivated in 

 water. Here it was found that the anatomical structure of the 



stem had been caused to approach that of the roots in several 

 ways, namely, by a considerable lenf^thcning of the elementary 

 organs, by a lessening of the number of sclerenchymatic cells and 

 a decrease in the thickness of their walls. It will be remembered 

 here that the stem was kept for the most part under water. 



The results of the experiments are summed up by the re- 

 viewer. First, the structure of the wood of the stem is not so 

 constant, not so sure to be transmitted from one generation to 

 the following, as has been hitherto supposed. If it is proven that 

 through a long line of generations, the inner structure of the stem 

 of any given species has remained constant, it can also be proven 

 that the environment has remained about the same. When this 



r 



is changed, then the anatomy of the stem changes. The plant, 

 therefore, inherits only the ability to produce a certain series of 



