Autumnal Coloration of Leaves 



By G. E. Stone 





At the meeting of the Society for Plant Morphology and 

 Physiology held at Columbia University in December, 1899, a 

 paper by Dr. D. T. MacDougal was read entitled " Influence of 

 Inversions of Temperature and varietal Currents of Air upon the 

 Distribution of Plants." 



*#• The observations upon which the results were obtained were 

 made in Arizona, and among other things brought out in this 

 paper was the fact that the autumnal colorations of leaves first 

 showed itself on the low elevations. 



During a brief discussion of the paper some other observers 

 took exception to this statement, and it was stated that in the 

 Allegheny region the autumnal tints first showed themselves upon 

 the mountains, or higher elevations. 



Our observations here. in Massachusetts have coincided with 

 those of Dr. MacDougal in Arizona, namely that the autumnal 

 tints are first seen in the lowlands and not upon the hills and 

 mountains. Whether there exists a different state of affairs in the 

 Alleghenies which causes autumnal coloration to appear first upon 

 the higher elevation, thus offering an exception to the condition 

 of affairs in New England and Arizona would be well worth know- 



ing 



A 



color are 



the red maple and poison sumac of the swamps. These species, 

 on account of their location, are subject to the frosts when those 

 in the highlands are not, and this factor alone would hasteij their 

 coloration. 



There are, however, many external influences which determine 

 coloration in trees which should be taken into consideration. 



The exceedingly dry season of '95-96 caused many upland 

 trees to exhibit premature coloration on account of drought, and 

 in like manner did the wet season of '97 cause many swamp species 

 to show their tints as early as the middle of August on account 



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