106 



HUTCHINSON'S POPULAR BOTANY 



sion, the veins of which are coarsely netted, and it is joined to the 

 blade by a very narrow neck. The blade consists of a roundish, thick, 

 leathery plate, having strong, hidden, parallel veins, which spread nearly at 

 right angles from the central vein or midrib to the margin, and is bordered 

 with a row of strong, stiff, tooth-like hairs. "When young, the two sides of 

 the blade are placed face to face, and the teeth cross each other; after- 

 wards, when full grown, the sides spread flat, or nearly so, and the teeth 



then form a firm spreading border. On 

 each half of the blade stand three delicate, 

 almost invisible bristles, uniformly arranged 

 in a triangle ; and these are the true sensitive 

 organs of the plant. Let but one of the 

 bristles be touched, and the two sides of the 

 blade spring together with considerable force, 

 the marginal teeth crossing each other so as 

 to enclose securely any small object which 

 may have caused the irritation, be it insect, 

 straw, or seductive morsel of steak. Wonder- 

 ful to relate, no other part of the leaf is 

 sensible to external impressions. In vain is 

 the back of the leaf disturbed, or the smooth 

 glandular surface pricked and tickled ; unless 

 you jar one of the bristles, no irritability is 

 excited, and the blades remain immovably 

 open. The moment the shock is communi- 

 cated through one of the bristles, the collapse 

 is effected, the leaf assuming altogether the 

 appearance of an iron rabbit-trap when it has 

 closed upon its prey ; and if, at this time, an 

 attempt is made to open the leaf, it is vio- 

 lently resisted, in consequence of the rigidity 

 of the parallel veins. 



Like the Sundews, Dioncea feeds upon the 

 insects which it catches, for it possesses, like 

 them, the power of digestion. Dr. Burdon 

 Sanderson, in a lecture delivered at the Royal Institution in 1874, thus 

 referred to the digestive power of this plant : 



" When we call this process digestion, we have a definite meaning. 

 We mean that it is of the same nature as that by which we ourselves, 

 and the higher animals in general, convert the food they have swallowed 

 into a form and condition suitable to be absorbed, and thus available for 

 the maintenance of bodily life. We will compare the digestion of Dioncea 

 with that which in man and animals we call digestion proper, the process 

 by which the nitrogenous constituents of food are rendered fit for 



FIG. 140. FLOWKR OF BLADDER- 

 WORT (Utricularia vulgaris). 



This type of flower is called personate. The 

 lips are closed, as in the flowers of Snapdragon 

 and Calceolaria, only bees being able to force 

 them apart, in order to reach the nectar in 

 the conical spur. 



