HAIRS AND THEIR USE 



size of a pea, and are most ingeniously contrived to catch 

 small water-animalcula. The general idea of the bladder- 

 wort is exactly that of the eel-pots so common in some parts 

 of the Thames. There is a small flap which acts as a trap- 

 door. Small creatures probably take refuge in the bladders 

 when pursued by the larger water-fleas, etc., for it must seem 

 to them to be a safe and secure retreat. 



But once within the door, they are imprisoned and cannot 

 find their way out again. They perish inside and their 

 bodies are digested by the plant ; on the inside of the bladder 

 there are gland hairs which also secrete a digestive fluid. 



The bladderwort is dangerous to fish, for the little fry, 

 when quite small, run their heads and gills into the bladders 

 and are suffocated. 



There are a great many kinds of Utricularia, and they 

 occur in most of the great floral regions. 



One of them has chosen a very extraordinary and curious 

 situation. It lives inside the little cups of water which, as 

 we have already mentioned, are formed by the leaves of some 

 Bromeliads. The insects in the water which ought to 

 nourish the Bromeliad (Tillandsia) are really used by the 

 Utricularia. Other Utricularias live in damp earth, moss, etc. 



It is not only by traps and pitfalls that plants catch 

 insects : many have specially modified hairs which are quite 

 efficient insect-catchers. 



Hairs are used by plants for many different purposes, and 

 it is rather interesting to see how quite a simple organ like 

 a hair can be altered. The stinging hair of the nettle has 

 already been mentioned ; many grasses possess minute, rough, 

 flinty hairs, which probably prevent snails from eating them. 

 That also is probably the reason of the strong, rough, coarse 

 hairs which cover the Borage and the Comfrey. 



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