36 PLANT-LIFE ON LAND [ch. 



on the open hillside. The explanation of the success 

 of mowing about midsummer day is probably to be 

 found in its effect on nutrition. The plant has at that 

 time of year devoted all, or at least most of its 

 floating capital of stored food, to the business of the 

 formation of leaves and spores. But the leaves are 

 the nourishing organs, and they are mown before 

 their function is fully started. Thus the plant loses 

 the capital it has embarked. There may be a sufficient 

 residuum of stored food left to produce a second 

 or even a third formation of leaves ; but repeated 

 mowings will so deplete the rhizome as to lead finally 

 to death by starvation. 



An observant friend in the Highlands has pointed 

 out to me that mowing is more efiective at low levels 

 where the growth is strong, than higher on the hills 

 where the Fern is relatively stunted. This is probably 

 to be explained by the fact that where growth of the 

 leafage of the year is favoured, the plant draws more 

 deeply on its floating capital than where the circum- 

 stances are less encouraging. The hill plants will 

 probably retain a larger proportion of their supply in 

 the underground stock, and so be better able to renew 

 the efibrt at leaf-formation. 



But nutrition is not the only function of the 

 Bracken leaf. In fully matured plants theleaf also bears 

 the organs of propagation. If the ultimate branch- 

 ings of the leaf be carefully examined, it will be found 



