BY ALEX. G. HAMILTON. 53 



ing on it, smear themselves with pollen from the fertile stamens, 

 which at that stage have not reached the pendent position. They 

 then bore into the disc through the staminodes, and continue 

 eating the inner surface, at the same time j^lacing the pollen on 

 the stigmas. Thus it would seem that the first few flowers 

 opening would certainly be self-fertilised. But all opening after 

 the first day would be likely to be cross-fertilised, as the beetles 

 would bring pollen from the flowers previously visited. Almost 

 every flower on two trees which I watched has developed a fruit, 

 a fact not be wondered at when the large number of beetles 

 visiting the tree is considered. 



When I first saw the beetles at work I was inclined to think 

 that this was a case similar to the Yucca, in which the Yucca- 

 moth stuffs the 23ollen into the hollow stigmas after depositing 

 their eggs in the ovulary. But by careful observation I made 

 sure that the bettles did not deposit their eggs about the flower, 

 and that when the ring of stamens and staminodes dropped ofi", 

 the disc was left clear of everything. And in sections since cut 

 of large numbers of fruit, I have never found any larvae. I am, 

 therefore, quite certain that the process of fertilisation is as I 

 have described it. A remarkable fact is, that notwithstanding 

 the strong scent of some hundreds of blossoms on this ti-ee. which 

 w^as perceptible 20 yards away, no other insect visited them; 

 although not far away there were hundreds of bees, butterflies, 

 flies and other species of beetles at work on the blossoms of a 

 myrtle bush. It would seem as if the plant deliberately laid 

 itself out to attract the one species only. 



The most important question arising out of this extraordinary 

 method of fertilisation is how it could have originated. Here we 

 have a flower so constructed as to cut off pollen from its stigmas 

 completely, unless it is placed there by extraneous means. What 

 were the steps by which the plant developed a large number of 

 sterile stamens adapted — first, to cut off access of its pollen; and, 

 second, to be attractive to beetles as food ? And what first caused 

 the beetles to visit the flower and so undo the self-imposed sterility 

 of the plant 1 To these questions I am unable to offer any reply. 



