I874-] CLIMBING AND INSECTIVOROUS PLANTS. 499 



[During the summer of 1874 he was at work on the genus 

 Utricularia, and he wrote (July 16th) to Sir J. D. Hooker 

 giving some account of the progress of his work : — 



" I am rather glad you have not been able to send Utricu- 

 laria, for the common species has driven F. and me almost 

 mad. The structure is most complex. The bladders catch 

 a multitude of Entomostraca, and larvae of insects. The 

 mechanism for capture is excellent. But there is much that 

 we cannot understand. From what I have seen to-day, I 

 strongly suspect that it is necrophagous, i.e. that it cannot 

 digest, but absorbs decaying matter." 



He was indebted to Lady Dorothy Nevill for specimens of 

 the curious Utricularia Montana, which is not aquatic like the 

 European species, but grows among the moss and debris on 

 the branches of trees. To this species the following letter 

 refers :] 



C. Darwin to Lady Dorothy Nevill. 



Down September 18 [1874]. 



Dear Lady Dorothy Nevill, — I am so much obliged 

 to you. I was so convinced that the bladders were with the 

 leaves that I never thought of removing the moss, and this 

 was very stupid of me. The great solid bladder-like swell- 

 ings almost on the surface are wonderful objects, but are not 

 the true bladders. These I found on the roots near the sur- 

 face, and down to a depth of two inches in the sand. They 

 are as transparent as glass, from -^ to yj-g- of an inch in size, 

 and hollow. They have all the important points of structure 

 of the bladders of the floating English species, and I felt 

 confident I should find captured prey. And so I have to my 

 delight in two bladders, with clear proof that they had ab- 

 sorbed food from the decaying mass. For Utricularia is a 

 carrion-feeder, and not strictly carnivorous like Drosera. 



The great solid bladder-like bodies, I believe, are reser- 

 voirs of water like a camel's stomach. As soon as I have 

 made a few more observations, I mean to be so cruel as to 

 give your plant no water, and observe whether the great 



