PLANTS OF THE MOORLAND 91 



back that they meet one another beneath, shutting in 

 the under surface, which bears the transpiration pores 

 or stomata. This, as we have seen, is characteristic 

 of Heaths, and Professor Miall notes that a certain 

 moorland grass (Nardus stricta), which grows in 

 close tufts, has the same habit. " Its leaves look wiry 

 or even bristle-like, because they are rolled into 

 slender and rather stiff hollow cylinders." This shel- 

 tering of the transpiration surface by rolling round 

 the margins will lessen the loss of water in summer 

 drought; but Professor Miall points out in his delight- 

 ful "Round the Year" (1896), a book that compels 

 one to think, that the rolling round is seen in some 

 plants which are little liable to drought. It may be a 

 protection against wind, which forces loss of water 

 from the leaves into the air, and yet reduces the tem- 

 perature so that the absorption of water from the 

 soil is difficult. " Drought and cold and wind all tend 

 to parch the tissues or, at least, to cut off the supply 

 of water taken in by the roots, and diminished trans- 

 piration is the remedy of nature for all three con- 

 tingencies." One other idea must be noted, however, 

 that sometimes when there is plenty of water in the 

 soil, it is chemically of such a nature that its absorp- 

 tion is difficult. It is too full of organic salts. To 

 sum up, the rolled-round leaves of the Crowberry, the 

 Heath, and some other moorland plants are well 

 suited for economising water, not only when it is 

 scarce, not only when there is danger of losing top 

 much, but also when it is abundant in the surround- 

 ing soil yet difficult to absorb. 



Another heath plant is the Bearberry (Arcto- 

 staphylos uva-ursi), with trailing woody branches, 



