144 The Plant World. 



sands of which dunes are composed, and the various forms which 

 they assume, and the apphcation of these generaUzations to the 

 local conditions of New Zealand. 



The botanical section begins with a consideration of the 

 conditions determining the plant life of the local dunes. And 

 here, again, wind-toleration is considered to be the prime factor. 

 Then follow full descriptions of 13 native New Zealand plants 

 that are either sand-binders or sand-collectors. The paper 

 concludes with a detailed study of the dune-plant associations 

 of western Wellington. The practical economic question, re- 

 lating to the control and fixing of dunes,is reserved for a future 

 report, the present paper being designed to supply the prelim- 

 inary data necessary for an intelligent solution of the problem. 



San Bernardino, Cal. 



THE STARCH CONTENT OF LEAVES DROPPED IN 



AUTUMN. 



By L. Iv. Harter. 



It is generally believed that carbon assimilation and elabor- 

 ation of plant foods in practically all deciduous trees, bushes, 

 etc., cease at the approach of maturity of the leaf and the com- 

 ing on of autumn. It is further supposed that the products of 

 assimilation that are already in the leaves would be largely trans- 

 ported to other parts of the plant before frosts in the fall or be- 

 fore the leaves are dropped. If such is the case, the autumn 

 leaves that fall to the ground after maturity would not contain 

 much carbohydrate in the form of starch or sugars. 



During the summer of 1909 the writer undertook to trace the 

 changes taking place in the amount of starch formed in the leaves 

 of Liquidamher styraciflua at different periods, and collected 

 material for that purpose August 17, 1909, September 15, 1909, 

 October 23, 1909, and October 28, 1909. Doubtless the leaves 

 collected on the first two dates were in an active state of assimi- 

 lation. The leaves collected on October 23 had taken on their 

 autumn coloration and to all appearances contained little or no 

 chlorophyll, while the material collected on October 28 was 

 leaves freshly fallen and in most cases contained a noticeable 

 amount of red pigment. The starch in the leaves collected at 



