682 THE POPULAR SCIENCE MONTHLY. 



diately fold her leaflets. This same effect is also induced by cold and 

 darkness. 



The flowers of many plants are found in certain ways to be greatly 

 dependent on temperature and on light. They open in the morning 

 when the sun has reached a certain place in the heavens, and close 

 again at a stated time at night. 



Some plants can open their flowers or parts of them very quick- 

 ly. For instance, the Martha of the tropics, on the approach of an 

 insect, ejects its pollen suddenly, and then as quickly closes the en- 

 trance to the flower, and refuses the insect admission. Motion of a 

 different nature is shown by the climbing plants that were so closely 

 studied by Darwin. 



At times one hears or reads of the wandering of plants. But how 

 is it possible that firmly rooted plants should be capable of changing 

 their position ? And yet this is so. In most cases, it is true, the re- 

 movals are made merely by the seeds and not by the plant as a whole. 

 Sometimes, however, the whole plant starts out to travel ; this is gener- 

 ally accomplished by the friendly aid of the wind. The world-famed 

 Anastatica, the rose of Jericho, comes in for mention here. It has the 

 peculiar property of spreading out its branches, that at other times are 

 folded to a ball, whenever its roots are moistened by water. In its 

 dreary home, the deserts surrounding the Red Sea, it is but slightly 

 fastened in the loose sand. Without much trouble it is torn from its 

 bed by the winds and borne to great distances. 



Some species of algse, which form green or yellowish-green masses 

 on the surface of placid waters, are thrown on the land by inundations, 

 and are kept back after the waters have subsided, and finally dry into 

 a peculiar matted substance not unlike coarse packing-paper. This 

 is taken up by a strong wind and carried away. These wandering 

 masses, which some people have readily connected with superstitious 

 conceptions, are called " meteor paper." The water-pest is another 

 plant that spreads itself in the same manner ; as far as can be ascer- 

 tained, it was transplanted in 1835 from North America to Ireland, and 

 from there to the European Continent. 



The majority of plants, however, are spread by the aid of their 

 seeds, which are covered with hair or a fine woolen fiber, and can thus 

 be easily scattered ahout by the winds, just as some varieties of spi- 

 ders, in spring and autumn time, clinging to a silken thread, intrust 

 to the winds the choice of their future home. 



Let us now turn to a group of plants which claim interest by being 

 possessed of a faculty generally attributed to animals only. Not 

 satisfied with the nourishment which the humidity of the soil and the 

 atmosphere afford, they seek to obtain a kind of food which Nature 

 has, strictly speaking, denied them. I mean the insect-eating plants. 



The knowledge of the existence of these curious beings is not 

 really of a recent date, but former investigations remained unheeded. 



