374 



Marvels of the Universe 



A PLANT THAT SETS WATER TRAPS 



BY JOHN J. WARD, F.E.S. 



I HAVE already introduced to the readers of this work some strange plants which catch and eat 

 insects, and in that article I pointed out that this habit was the natural outcome of those plants 

 living in boggy and wet situations, because in such places the soil lacks a sufficiency of the nitro- 

 genous matter so necessary in the plant economy. Here I want to introduce another curious plant 

 with similar habits, but in this case one that has disposed of its roots entirely and become com- 

 pletely aquatic. The plant 

 in question is the English 

 Bladderwort (of which 

 there are three recognized 

 species) of the deep pools 

 and sluggish waters. In 

 the first place, it is ob- 

 vious that the Bladder- 

 wort by becoming aquatic 

 has made an advantageous 

 change. Its roots were 

 more or less useless for 

 feeding purposes, owing to 

 the fact that there was no 

 material on which they 

 could feed. Therefore, 

 their natural function was 

 lost, and they, in conse- 

 quence, have disappeared. 

 At whatever remote period 

 in its evolution the Blad- 

 derwort lost its roots, we 

 may assume that it then 

 grew in watery surround- 

 ings. That being allowed, 

 we can imagine that the 

 next thing that would 

 happen would be that the 

 plant would find itself 

 afloat. From thence its 

 possibilities of development would improve. In floating about it would doubtless come in 

 contact with decaying animal and other matter, which would provide it with those nitrates 

 which had hitherto been its main want. And, as in the case of the insectivorous plants 

 previously considered, its primitive glandular structures would scarcely lose the opportunity of 

 making the best use of this all-important material. That, possibly, was the beginning of things, 

 and then, by a process of natural selection combined with what the philosopher Bergson defines as 

 " the internal push that has carried life, bj- more and more complex forms, to higher and higher 

 destinies," the Bladderwort would evolve the complex mechanism that we find it possessing to-day. 

 To-day, indeed, it is an exceedingly successful water-trapper. It floats near the surface, with 

 its traps aU set for minute insects, water-fleas, the small fry of fishes, etc. The traps are popularly 





Photo bii] 



THE SPINY SPIDER. 



A view from the underside of a remarkable Spider which is a 

 is three-quarters of an inch across. It has a white body, spotted ' 

 spines, as well as the legs and jaws, are also red. 



iDr. E. J. Spitta. 



ve of Trinidad. It 

 red, and the six 



