Puiver of Muvenicnt in PUinta. Ho 



the Texan prairies, wliicli invariably grew with the edges of its 

 leaves north and south, the faces or surfaces being east and west. 

 This was to expose both surfaces to an equal amount of light, 

 there being in this plant an equal number of stomuta on both 

 surfaces. Trappers used this plant as a compass on dark nights 

 to find their way by, and even in the daytime it was a guide to 

 those who might be lost on the prairies. The sleep of flowers 

 was, like that of leaves, a provision against the ill eft'ects of too 

 great radiation. The direction, not the intensity, of light was 

 that which governed both positive and negative heliotropism. 



Mr. Worsley-Benison then referred to induced movements in 

 leaves, such as might be seen in Mimosa and Desinodium, and 

 in sundew and Venus's fly-trap, where insects were the agents, 

 sacrificing their lives in the process ; also to such cases as the 

 leaves of Scliinim and llJni.i, which could be made to execute a 

 dance by throwing them into water. In Utrioildria, or bladder- 

 wort, the fine hair-like leaves were furnished with floating 

 bladders. These possessed valves which closed with a fatal 

 snap, when the wanderings of aquatic insects or yovmg fishes led 

 them to exanhne the bladders. In illustration Mr. Worsley- 

 Benison stated that Mr. G. K. Sims, of Oxford, recently 

 noticed that some 200 or 300 young perch in his aquai'ium had 

 unaccountably disappeared. The aquarium had large quan- 

 tities of bladder-wort growing in it, and on investigation it was 

 found that many of the small fry had been entrapped by the 

 bladders, some by the head, and others by the tail. 



Finally, Mr. Worsley-Benison brought his address to a con- 

 clusion by referring to the induced movements in floral-organ?, 

 seen in the irritability of stamens in the barberry, pellitory, 

 nettle, saxifrage, rue, grass of Parnassus, and periwinkle ; in 

 the movements of the styles of the passion-flower, cactuses, 

 and others ; in the mutual approach of stamens and styles in 

 the fuchsia and the mallows ; and in the raising and lowering 

 of the lahelhnn of many orchids, and the central parts of 

 the same flowers. All these cases, he said, except the last, and 

 those of the leaves, had to do with fertilizing processes ; those of 

 the leaves of Dro.sera and Dionaa, and of the bladders of Utricic- 

 larid, with the actual nutrition of the plant. 



3 fctP 1888 



