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THE POPULAR SCIENCE MONTHLY. 



mens of the berberry, etc., and is then directly connected with the pro- 

 cess of fertilization of the ovule. In JStylidium, an Australian genus, 

 the style and filaments are adherent into a column, which hangs over 

 on one side of the flower. When touched, it rises up and springs over 

 to the opposite side, at the same time opening its anthers and scatter- 

 ing the pollen. The stamens of the various species of Herberts and Maho- 

 nia, to the former of which our common berberry belongs, exhibit this 

 irritability to a remarkable degree. If touched with a pin or other 

 object at the base of the inside face of the filament, the stamen will 

 spring violently forward from its place within the petal, so as to bring 



Fig. 8. 



the anther into contact with the stigma, as shown in Fig. 8, and will 

 after a time slowly resume its original position. At first sight it may 

 s'eem as if this contrivance were intended to insure the fertilization of 

 the pistil from the pollen of its own flower. In reality, however, the 

 reverse is the case ; the excitation takes place in Nature when an insect 

 entering the flower, for the sake of the honey in the glands at the base 

 of the pistil, touches the inside of one of the stamens. The pollen is 

 thus thrown on to the head or body of the insect, which carries it away 

 to the next flower it visits, and leaves some of it on the stigma, and 

 thus cross-fertilization instead of self-fertilization is secured. Similar 

 motion of the stamens toward the pistil, but spontaneous, takes place 

 in the case of the London Pride, and other species of Saxifraga. 



Elasticity is, indeed, a common property of organized tissue, though 

 it is not often developed to so evident an extent. In the " touch-me- 

 not," or Impatiens, we have a familiar instance in the seed-vessel, 

 which, if touched when nearly ripe, suddenly coils back, throwing the 

 seeds to a considerable distance. The "squirting cucumber" (Mo- 

 mordica elateriuni) marks the period of ripeness by the fruit separat- 

 ing from its stalk, and expelling the seeds and juice with great violence. 

 Mr. Thomas Meehan described a remarkable instance of elasticity at a 

 recent meeting of the Academy of Natural Sciences ot Philadelphia. 

 The seeds or, as would appear from his description, more correctly 

 the embryos of the seeds of the American " witch-hazel " (Hamame- 



