TFIE FACTORS OF ORGANIC EVOLUTIOIT FROM A 

 BOTANICAL STANDPOINT.' 



By Prof. L. H. Bailey. 



The Suevival of the Unlike. 



We all agree that there has been and is evolution; but we probably 

 all disagree as to the exact agencies and forces which have been and 

 are responsible for it. The subject of the agencies and vehicles of 

 evolution has been gone over repeatedly and carefully for the animal 

 creation, but there is comparatively little similar research and specula- 

 tion for the plant creation. This deficiency upon the plant side is my 

 excuse for calling your attention, in a popular way, to a few suggestions 

 respecting the continuing creation of the vegetable world, and to a 

 somewhat discursive consideration of a number of illustrations of the 

 methods of advance of plant types. 



1, NATURE OF THE DIVERGENCE OF THE PLANT AND ANIMAL, 



It is self-evident that the development of life ui^ou our planet has 

 taken place along two divergent lines. These lines originated at a 

 common ]3oint. This common life-plasma was probably at first more 

 animal-like than jilant-like. The stage in which this life-plasma first 

 began to assume plant-like functions is closely and possibly exactly 

 preserved to us in that great class of organisms which are known as 

 mycetozoa when studied by zoologists and as myxomycetes when 

 studied by botanists. At one stage of their existence these organisms 

 are amoeba-like, that is, animal-like, but at another stage tliey are 

 sporiferous or plant like. The initial divergencies in organisms were 

 no doubt concerned chiefly in the methods of appropriating food, the 

 animal-like organisms apprehending their food at a more or less 

 definite point, and the plant-like organisms absorbing food through- 

 out the greater or even the entire part of their periphery. It is not 

 my purpose to trace the particular steps or methods of these diver- 

 gencies, but to call your attention to what I believe' to be a funda- 

 mental distinction between the two lines of development, and one 



' Read before the American Philosopliical Society May 1, 1896. Printed in the 

 Proceedings of tlie American Philosophical Society, Vol. XXXV, 1896. 



453 



