86 



trap' leaves — sets forth its traps and waits for its prey; which 

 brings us to a consideration of traps in general and in particular 

 to those of the plant that Goebel has been quoted as declaring the 

 most wonderful plant of all. 



What should we expect of a trap? In order to be effective it 

 should be well located or failing this should be made attractive to 

 the victim. Of location we shall have more to say below : of at- 

 traction much might be written. Thus, in the case of the Sundew, 

 the leaves, deadly though they are, are supposed to attract by vir- 

 tue of their appearance. The colouring of Sarracenia, it is sug- 

 gested, may have this function. 



Traps, like jails, must prevent escape unless (and this hap- 

 pens rarely) the victim is killed at once. It is probable in the case 

 of the A^enus flytrap that the psychology of the fly alone renders 

 the trap effective, for the struggles of the insect, by acting as a 

 repeated stimulation, seems to prevent opening of the trap. 



Additional merits would consist in a self-getting mechanism 

 and a selective capacity for the rejection of unsuitable material. 

 This last, perhaps, is expecting too much, but we shall see. 



In the tropical and temperate regions of the earth are to be 

 found the more than two hundred species of the genus Utricidaria 

 — the Bladderworts — flowering plants that inhabit a wide variety 

 of situations. Some are epiphytes in. the rain-forests of the tropics, 

 others affect more lowly stations and grow on moss and humus. 

 Others again, including all the species of the temperate zones, are 

 aquatics and the flowering stems alone appear above water to bear 

 the showy blue, yellow or white flowers. In one remarkable case 

 the plant lives only in the water collected in the bases of the leaves 

 of a large Tillandsia and Gardner (1846) tells us : '. . . propagates 

 itself by runners, which it throws out from the base of the flower 

 stem; this runner is always found directing itself towards the near- 

 est Tillandsia, when it inserts its point into the water and gives 

 origin to a new plant, which, in its turn, sends out another shoot ; in 

 this manner I have seen not less than six plants united.' 



It is an aquatic species of the North Temperate zone — Utricu- 

 laria gibba L — that is the subject of the following description. 



