1898.' 



071 a YovTisliire Moor. 



627 



but crumble slowly away. They are very small, densely crowded, 

 and ranged ou the branch in four regular rows. A good thin section 

 through a leaf is not easy to cut ; when you get one, you find that 

 the interior is largely occupied by irregular air spaces, and that the 

 stomates are sunk in a deep groove on the under side of the leaf, 

 where they are further sheltered by hairs. 



Fig. 5. — Cross-leaved Heath {Erica tetraUx); with part of a branch, 

 enlarged ; a leaf seen from the under side ; and a section of a leaf. 



Ling is a plant of slow growth, and a stem which showed seven- 

 teen annual rings was only a centimetre in diameter. Stems of 

 greater age than this are rare. After ten or twelve years the plants 

 flower scantily, and exhibit other signs of age. Then the common 

 practice is to burn them off. 



As we travel south, we find the ling getting smaller and smaller. 

 In Scotland it is often waist-deep, in Yorkshire knee-deep, on 

 Dartmoor only ankle-deep. On the moors of the south of England 

 the ling is generally much mixed up with grasses, as also on the 

 verges of the Yorkshire moors. In Cornwall it may grow so close 

 to sea level that it is wet with salt spray in every storm, and its tufts 



