356 PROCEEDINGS OF THE ACADEMY OF [June, 



of the tree's original growth from the grouud. The following 

 year the incurve extenrled down to the six or seven-year wood, 

 and the upper portion recurved so that it might again assume a 

 perpendicular position. No further curving occurred in after 

 years. The tree is yec one of the curiosities on my grounds. 



Following this was an experiment with a Lawsou Cypress, 

 Cupressm Laiosoniana. The results were similar, the incurving 

 being just after active growth in spring. 



So far we have the lesson from direct experiment. But when 

 we look around us we see the bending power abundantly illus- 

 trated. The Galena Weeping Elm, a form of Ulmus Americana, 

 grafted on stems eight or ten feet high, starts from the first with 

 cord-like pendent branches reaching to the grouud. But I have 

 trees between thirty and forty years old that are nearly as many 

 feet high. I have never seen an erect one-year-old branch on the 

 trees. At the end of every branch there is pendent a growth of 

 two or three years. For several yeax's I have watched a leading 

 branch that is straight and nearly horizontal, now over twenty feet 

 in length ; a pendent growth of three years is always at its termi- 

 nus. I find that in June the third year's growth straightens, the 

 new growth still forming a continuous three-year bend. The Weep- 

 ing Willow will occasionally make a few vigorous straight stems to 

 aid in the upward growth, but the majority of the curved 

 branches take to straightening after two or three years. The 

 Hemlock Spruce, Abies canadensis, curves its new growth, which 

 continues curved till the next season, when it rapidly becomes 

 erect, the new growth taking the curve of the previous year. 



The most interesting features of the study relate to the incurv- 

 ing and recurving of very old branches. In many trees there is 

 no evidence of a tendency to bend till after the fifth year. For 

 some ten years after this, or in ten- or fifteen-year-old wood, the 

 phenomena is common. It may often be seen in the Tulip Poplar, 

 Liriodendron tulipifera, the White Ash, Fraxinu-'^ Americana, 

 the Pear tree, and many others. One of the best illustrations is 

 afforded by the Hoi'se Chestnut, jKicxdus Hippocastamim. The 

 branches all keep at an acute angle till the tree reaches an age of 

 about twenty-five years. Then the ten-year-old branches begin to 

 droop from near the basal region at the trunk. They spend several 

 years in curving downward, and then make an incurve between 



