SUNDEWS AND VENUS FLYTRAP 



4U 



In other rather common plants, the sundews, insects are 

 caught by a sticky secretion which proceeds from hairs on the 

 leaves. In one of the commonest sundews (Fig. 312) the leaves 

 consist of a roundish blade, borne on a moderately long petiole. 

 On the inner surface and round the margin of the blade are 

 borne a considerable number of short bristles, each terminating 

 in a knob, which is covered with a clear, sticky liquid. When a 

 small insect touches one of the sticky knobs it is held fast, and 

 the hairs at once begin to 

 close over it, as shown in 

 Fig. 313. Here it soon 

 dies and then usually re- 

 mains for many days, 

 while the leaf pours out 

 a juice by which the 

 soluble parts of the insect 

 are digested. The liquid 

 containing the digested 

 portions is then absorbed 



by the leaf and contrib- 



, , , ,. The one at the left has all its tentacles closed 



Utes an important part Ot over cap tured prey ; the one at the right has 



the nourishment of the onl y half of them thus closed. Somewhat 



, ., ., ,. . , magnified. After Darwin 



plant, while the undigested 



fragments, such as legs, wing cases, and so on, remain on the 

 surface of the leaf or may drop off after the hairs let go their 

 hold on the captive insect. 



In the Venus flytrap, which grows in the sandy regions of 

 eastern North Carolina, the mechanism for catching insects is 

 still more remarkable. The leaves, as shown in Fig. 314, termi- 

 nate in a hinged portion, which is surrounded by a fringe of 

 stiff bristles. On the inside of each half of the trap grow three 

 short hairs. The trap is so sensitive that when these hairs are 

 touched it closes with a jerk and very generally succeeds in 

 capturing the fly or other insect which has sprung it. The 

 imprisoned insect then dies and is digested, somewhat as in the 



FIG. 313. Leaves of sundew 



