NOTES ON THE GEOLOGIC HISTORY OF PLATANUS 



EDWARD W. BERRY 



The Johns Hopkins University, Baltimore, Mil. 



' Tlie Plane-trees, Sycamores, and Buttonball or Buttonwood 

 trees, comprise the family Platanaceae and well repay consider- 

 ation. Not only are some of them among the most attractive, 

 but they are the most massive among our deciduous trees, even if 

 they are not the tallest. 



They are a widely scattered but waning type in these modern 

 days, for the family consists of the single genus Platanus with 

 only six or seven species of Southwestern Asia, Eastern and Wes- 

 ern North America, Mexico and Central America. The mem- 

 bers of this small group are very uniform in general appearance, 

 with large deciduous leaves, minute flowers in closely packed 

 pendulous heads that remain attached during the winter, during 

 which season the pappose fruits are widely distributed by the 

 winds. The leafstalks are enlarged at the base to enclose the 

 winter buds; and the bark is very thin, smooth, and pale green 

 or whitish. The wood is likewise rather uniform, in all being 

 light brownish or reddish in color with wide rays. It splits 

 poorh^ and in general is of secondary commercial importance. 



The known ancestral history of these trees extends back into 

 the dim past a staggering number of thousands or even millions 

 of years. A still flourishing forest giant with a height of 

 upwards of 170 feet and a trunk diameter of ten or eleven feet, 

 which are the dimensions of some individuals of our American 

 sycamore (Platanus occidentalis L.), has survived more changes in 

 human historj^ than almost any royal or ducal line. Columbus 

 might have seen a still surviving one as a young tree had he 

 penetrated inland along the river bottoms of our southern 

 states. The family history is surpassingly more majestic for it 

 extends back to the days when even the ape-man was a distant 

 promise and the reptilian tribe of animals were the lords of crea- 



. 1 



THE PLANT WORLD, VOL. 17, NO. 1, 1914 



