i64 THE STORY OF PLANT LIFE 



are flat or convex, and lie close to the ground, forming 

 a rosette from 3 to 4 in. in diameter. The margins of 

 the leaves are incurved. Their upper surfaces are 

 thickly covered with two sets of glandular hairs, 

 differing in the size of the glands and in the length 

 of their pedicels. The larger glands have a circular 

 outline as seen from above and are of moderate 

 thickness, they are divided by radiating partitions 

 into sixteen cells, containing light-green homogeneous 

 fluid." 



These glands contain a sticky fluid. Darwin drew 

 out a thread of one of these to a length of 18 in. On 

 a single leaf there may be as many as half a million 

 glands. If a small insect alights on a leaf it is 

 immediately caught, as a bird by bird-lime, in the 

 sticky fluid, entangling itself the more it struggles to 

 escape. The leaf margin curls over, and this serves 

 as a further means of imprisonment, and has the 

 efi'ect of pushing the prisoner more into the centre 

 into the thickest array of glands. Darwin counted 

 on four leaves as many as 132 insects. They are 

 digested by the pepsin-like secretion and contribute 

 to the nutriment of the plant. 



All parts of the British Isles afford stations for 

 the Butterwort, but it is more common in the West 

 of England and in Scotland and Ireland. It is also 

 found in the Channel Islands. 



Bogs form the principal habitat of the Butterwort. 

 It grows also by mountain rills, on wet rocks, in 

 Sphagnum swamps. It is found on sandy soil in wet 



