77 



elementary organs. What is to be made of the cell cut off from 

 the cambium, is determined by outward circumstances. The ex- 

 istence of a large variety of transitional forms among these elemen- 

 tary organs of the wood tissue is explained by this theory in a 

 much more reasonable way than by any functional theory which 

 can be suggested. 



J 



are which control the manner of 



growth, the author does not claim to know. By his experiments, 



however, he claims to have proven that water is a leading factor. 



As stem and root are accustomed to grow in different media, 



they therefore show a difference in their elementary organs. It 



must be possible to change the woody tissue of the stem to that 



of the root and vice versa. This latter possibility he claims to 

 have verified. 



The reviewer adds his own testimony to many of the conclu- 

 sions drawn from the experiments described, having carried on 

 similar experiments several years ago. A single sentence of the 

 reviewer gives the key to the whole article. This translated as 

 literally as possible is as follows : ** The anatomical structure de- 

 pends on the influence of outward circumstances, and is adapted 

 to the causes at work during the life of the plant, but this adapta- 

 tion does not necessarily involve the idea of function or pur- 



pose.'* 



E. L. G. 



Index to Recent American Botanical Literature. 



Abstamumng der Platancn. Johann Janko. (Bot. Jahrb. xi. 412- 

 458, pi. IX. & X). 



The important part which the American fossil representa- 

 tives of the genus Platamis play in this investigation is admi- 

 rably depicted by the author, in addition to which this article is 

 a welcome contribution to general pal^o-botany. The biblio- 

 graphy and table of synonomy for the fossil species is of great 

 value and is deserving of special mention. 

 Acalypha Virginica, Considcrata^ m Ordine alia Diffusione nel 



Veronese, A. Goiran. (Giorn. Bot. Ital. xxii. 134- 136). 

 Bald Cypress. — The Knees of the, N. S. Shaler. (Garden and 



Forest, iii. 57). 



A criticism of Dr. Lamborn*s hypothesis, indexed in the last 

 number of the BULLETIN. 



