8 BULLETIN OF THE NATURAL HISTORY SOCIETY. 



II. — The Nature and Methods of Phytobiological Study. 



Phytobiology, as we have s^eeii, is the study of adap- 

 tations, that is of the arrangements by which plants and 

 their parts are brought into responsive contact with 

 external influences. It investigates in all degrees the 

 effects upon plants of the external phenomena of the 

 world, that is, force in all its forms and matter in its 

 various states ; and considers as well the utilization of 

 these by plants in their organic necessities, /. c, nutrition, 

 locomotion, protection, reproduction, competition. From 

 the most general relationships of influences and necessities, 

 resulting in the formation of the primary organs of plants, 

 it proceeds through all grades to the most minute 

 analysis of details, explaining the most superficial char- 

 acteristics of form, size, color, position. 



The study of the reaction of the plant to the con- 

 ditions of its environment would be comparatively simple 

 were we concerned but with the present, and a com- 

 pletely plastic plant. But in fact all of the complexities 

 of relationships of the past, the resultant effects of which 

 we are accustomed to designate heredity^ together with a 

 little-understood internal constitution, of which variation 

 is the most important phase, and which may or may not 

 be included wntli heredity, — these two impose great 

 restrictions upon the operation of the present environ- 

 ment. Ever}' plant, and every part of it, represents the 

 resultant of an enormously complex inter-operation of tlie 

 influences of these three conditions — heredit}', internal 

 constitution and present environment, and each of these 

 plants and its parts is in a state of unstable equilibrium, 

 and readily alterable through movements in the environ- 

 ment. The delimitation of the effects of these influences 

 upon plants is the ideal of Phytobiology in its most 

 philosophical phases. 



