CHAPTER IV 

 THE IMPORTANCE OF HAIRS IN PLANT LIFE 



THE term " hair " in its widest sense includes all structures 

 that are developed from the outer skin of any part of the plant ; 

 root-hairs, the prickles of the rose, the hairs on stems and leaves, 

 the bristles on many fruits are all " hairs " in the botanical sense 

 of the word. It is evident at a glance that hairs play an 

 important part in plant life, and that their functions are very 

 varied. 



ABSORPTION AND DIGESTION. In germination the root-hairs, 

 as we have seen, are engaged in drinking in food material for the 

 young plant. As soon as the lateral roots are formed the root- 

 hairs behind the tips are engaged in the same work. This has 

 already been fully described (p. 22), therefore we now pass on to the 

 share hairs take in digestion under certain circumstances. There 

 are some plants that feed on insects and obtain their nitrogen 

 from the dead bodies of the insects they capture. These plants 

 are usually found, as one might expect, in soil deficient in nitrogen. 

 The Pitcher-plant, Sundew, Butterwort, and Bladderwort are 

 instances. If these be examined it will be found that the insect 

 is often entrapped by means of hairs on the structures concerned, 

 and in some cases the hairs secrete a fluid which enables the 

 plant to digest the body of the insect. In the Pitcher-plant 

 (Plate II.) the leaf -stalk is modified into three distinct parts : 

 a flattened leaflike lower part; a tendril and a pitcher, the 

 blade of the leaf forming the lid of the pitcher. The insect, 

 attracted by the bright colouring, is caught by the bristles of 

 the rim ; unable to escape owing to the fact that the bristles 

 point inwards, the insect falls into the pitcher and is drowned 

 in the liquid which it contains. In the Sundew the leaves are 



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