Preface. xiii 



planation. Were there but one ring, the blades of grass 

 and other plants that grew intermixed with the lychnis, 

 and which came into contact with it at all kinds of points 

 and all kinds of angles, would serve as so many ladders 

 by which the ant might reach a point on the stem above 

 the solitary ring, and so get at the nectar. The repeti- 

 tion of the rings would make this impossible, unless, 

 indeed, the ladder chanced to be set against the flower 

 itself, or against the uppermost extremity of the stem. 

 Doubtless, if the viscid ring were at the very top of the 

 stem, or if the calyx itself were viscid, the same result 

 would be obtained. And as a matter of fact this was 

 the arrangement in sundry plants, as in the Nottingham 

 Catch-fly {Silene nutans), where only the calyx and up- 

 permost stem were viscid, whereas in the English Catch- 

 fly {S. Anglica) the whole plant was sticky. The condi- 

 tion of the Lychnis viscaria, seemed intermediate to these. 

 The stem might perhaps have once been sticky all over ; 

 and then the viscidity have become limited on econo- 

 mical grounds to the nodes, and might in further ages 

 perhaps become limited stiU further to the top of the 

 stem. Nor were indications of such a possible event 

 wanting, for already the lowest nodes of the stem were, 

 as I found, destitute of viscid secretion. 



On my return home, I propounded my hypothesis 

 as to the functional significance of viscidity to Mr. 

 Darwin, of whose inexhaustible kindness in listening 

 patiently to the crude guesses of amateur naturalists I 



