252 



room and the plants exposed to a saturated atmosphere. At 

 first normal stems from ordinary growing plants were tested in 

 this way to see what would be the effect in the growth of tip and 

 basal end. It was found difficult to make a sharp distinction by ^ 

 means of the outgrowth of adventitious roots and stems. How- 

 ever, another means of determining how far the nature of the 

 growing substance remained true to its inherited tendency pre- 

 sented itself. This was the development of the so-called callous 

 at the cut end of the stems. In every case of the stems taken 

 from the normally upright growing plants, this callous developed 

 much faster at the lower end of the stem than at the upper. 

 This remained the same in whichever way the stem was placed. 

 There was no possibility of deception as to the real upper end oi 

 the stem by examining this callous. Now this process was re- 

 peated with the inverted plants with exactly the same results. 

 The organic upper end of the stem would be detected with per- 

 fect certainty by the difference in the formation of the callous. 



The author makes no attempt to explain this phenomenon. 

 It was found to be a characteristic of the plant in its normal con- 

 dition, and the experiments tried on the inverted stems proved 

 that in this case at least, the inner nature of the plant had not 

 undergone an entire change. Externally a complete change had 

 taken place so far as morphological characteristics were con- 



cerned. 



E. L. G. 



Zurich, Switzerland, July 28. 



Index to Recent American Botanical Literature. 



Agarics — North Auierlcan. Robt, K. Macadam. (Journ. Mycol. 



V. 58-64, Part I). 

 Albinism among Floivers. C. R. Orcutt. (West Am. Sci. vi. J])- 



A list of albino plants collected by the author in CaUfornia. 

 AlgcB of Minnesota — Soine. J. C. Arthur. (Reprinted from 



Bull. Minn. Acad. Nat. Sci. iii. 97-103). 

 American Magnolias. (Garden, xxxvi, 28). 

 Anemone cylindrica with Tnvolucels. H, J. Webber. (Amer. 



Nat. xxiii. 264). 



Found at Lincoln, Nebraska. 

 Aster— A Key to the Species of. Alfred C. Stokes. (Journ. 

 Trenton Soc. Nat. Hist. ii. $2^24). 



