K.— BOTANY. 201 



plants, of known genetical constitution, on four different types of soil 

 under precisely similar climatic conditions in one spot. 



Thanks to the kindness and keen interest of Mr. E. M. Marsden-Jones, 

 now an honorary associate on the staff of the Koyal Botanic Gardens, 

 Kew, the experiments are being made by him in his garden at Potterne, near 

 Devizes, in co-operation with Dr. W. B. Turrill. Four large raised beds, 

 37 feet by 10 feet, enclosed by old railway sleepers, have been made side 

 by side, and each has been filled with a distinct type of soil — clay, chalky 

 clay, calcareous sand and non-calcareous sand. Sets of the plants under 

 investigation are also being grown on the natural upper greensand soil 

 at Potterne and on the light sandy Kew soil in the Herbarium garden 

 ground. 



On each type of soil twenty-five individuals of each of six species are 

 now being grown, all being of known genetic origin. Climatic conditions 

 are being recorded throughout each year, and full records of all features 

 connected with the growth and behaviour of all the plants on the different 

 soils are being kept. 



This is now the fourth year of the experiment, but it is the first year 

 in which six different approved plants have been under cultivation. 



A full report of the work up to October of last year has just been 

 published in the ' Journal of Ecology,' and the following summary is 

 abridged from the annual report of Kew activities during the past year.* 



The species transplanted are Centaiirea nemoralis Jord., Silene vulgaris 

 Garcke, S. maritima L., Anihyllis vulneraria L., and Plantago major L., 

 while during this year Fragaria vesca L. has been added. 



It is interesting to find that the most obvious changes are taking place 

 in Silene vulgaris, S. maritima and Plantago major. 



Centaur ea nemoralis has shown little change, but the general tone is 

 better on the clays than on the sands, though flowering commenced first 

 on the latter. The mean number of stems per plant was higher on the 

 clays than on the sands. 



In Anthyllis vulneraria morphological changes of a qualitative nature 

 have not occurred, but some interesting facts regarding selection have 

 been obtained ; unfortunately a high death rate has occurred on the sand 

 and on Potterne soil. Edaphic factors are obviously important in causing 

 the known natural limitation of this species, and these should be con- 

 sidered when it is proposed to cultivate Anthyllis as a forage plant. The 

 transplant results suggest that on suitable land it would be a valuable 

 and relatively persistent crop. 



Plantago major has proved exceedingly plastic, even within five months 

 last year, and even more so this year. The original plant was a dwarf 

 form, and this habit has been very nearly retained on the sand and to a 

 less degree on the calcareous sand, but it has become markedly luxuriant 

 on the clay and somewhat less so on the chalky clay. 



Some plants of Silene vulgaris on the calcareous sand have developed 

 a markedly ' strict ' habit, similar to that which has been many times 

 observed in individuals among wild populations, and this may be found to 

 have a genetical basis. On the calcareous sand the foliage has developed 



* See Journal of Ecology, August 1930. Kew Bulletin, Appendix 1, 1930, pp. 45-47. 



