OF THE GENUS ULEX. 33 



think, say that this modification of the Furze plant is a protection 

 against excessive evaporation, whether from drought or cold winds. 



But what are we to say of the spiny character ? It has been 

 pointed out that spines are the direct outcome of the environment 

 of drought. Henslow brings forward many examples to support 

 this from various writers, who all agree that under extreme condi- 

 tions of dryness plants tend to produce spines, while when spiny 

 plants are grown with an abundant supply of water they tend to 

 lose their spines. A French observer — M. Lothelier — found that 

 on growing a spiny plant, Berberis vulgaris, in a damp atmosphere, 

 it bore no spinescent leaves ; but in a perfectly dry atmosphere it 

 produced spines only. His figures are certainly very striking and 

 show this clearly. 



My own observations on naturally grown seedlings of Ulex, to 

 some extent, support this view, for I have found that taking a large 

 number of seedlings from two equally exposed but different soils, 

 one humus and the other stony loam, that the percentage of 

 seedlings with trifoliate leaves is not only greater on humus soil 

 than on the stony loam ; but the spinescent character is more 

 quickly assumed in the latter case than in the former, and as the 

 humus soil holds more moisture, as is well known, than the stony 

 soil, it appears as if this were the direct cause of it. Nevertheless, 

 it would not be fair to state definitely that this is so, for there may 

 be many causes at work of which we are ignorant, and one which 

 would at once occur to any careful observer, is whether nutrition 

 does not produce some effect upon young seedlings, the difference 

 between the nutritive values of humus soil and stony loam being 

 at once apparent. 



At the same time, observations which I have made upon seed- 

 lings kept indoors, well exposed to light, in a sandy soil, and well 

 supplied with water, although perhaps not very conclusive, owing 

 to the short time during which I have been able to continue them, 

 tend to support the view put forward by other observers that the 

 presence of moisture tends to reduce the spinescent character. 



A seedling of Ulex Europceus, which had germinated in the 

 antumn, and had already produced fourteen trifoliate leaves, was 

 taken the following spring and planted in a flower pot, in sandy 

 loam. It was' kept in a warm room well exposed to light for many 



International Journal of Microscopy and Natural Science. 

 Third Series. Vol. VII. d 



