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VEGETABLE PHYSIOLOGY 



Dionsea affords an instance in which the movement of 

 capture is effected with greater rapidity. Like most of the 

 insectivorous plants it possesses a rosette of leaves which 

 rest upon the ground, and from the centre of the rosette it 

 gives off a single inflorescence. The leaves are very differ- 

 ent from those of Drosera. They have a flat expanded 

 petiole, at the end of which the lamina is attached by 

 a sort of joint. The lamina is roundish and is divided 



FIG. 100. LEAF OF Dioncea muscipula. 



1, open ; 2, closed ; 3, one of the sensitive spines ( x 50) ; 4, glands on 

 the surface of the leaf ( x 100). 



into two almost exactly similar halves, which are separated 

 by the midrib (fig. 100). The edge of each half is furnished 

 with a number of rigid teeth, and when the two halves are 

 folded together on a hinge which the midrib forms, the 

 teeth interlock with each other and a closed cavity is pre- 

 pared. On the upper surface of each half of the leaf, about 

 in the centre, are three short spines which project out- 

 wards and upwards. When either of these is touched twice 

 in rapid succession, the two lobes of the lamina become 



