362 PROCEEDINGS OF THE ACADEMY OF [June, 



what in their earher growth, that had curved the maiu stem iu the 

 effort to secure agaia the upright position. 



The facts adduced reveal to us a stupendous power iu plant life, 

 of which biologists hitherto have taken little heed. True we have 

 had casual noles of mushrooms lifting heavy paving stoces in a 

 single night ; of the roots of trees throwing down stone walls and 

 cleaving dense rocks in wedge-like fashion. I have myself re- 

 corded a case where a large tree growing on a rock had by accre- 

 tions below lifted the whole of its immense weight of trunk and 

 branches, so that it did seem that the trunk had elongated and 

 that a side branch had been carried several inches alcove its orig- 

 inal distance from the ground, but the great significance of these 

 facts has not been made clear to us. The action of light, of 

 gravitation, or of any external condition as a factor in direction 

 fails to satisfy us. It has been usual, especially of recent years, to 

 refer to conditions of environments as accounting for many of the 

 phenomena of life. Undoubtedly these conditions must operate to 

 some extent, or the speculations based on them could not command 

 the assent of so many great minds. We know, for instance, that 

 a plant growing vigorously in a cellar or dark room will incline 

 toward the light ; but I have shown in the Proceedings of the 

 Academy that in the dense darkness of mines species of Agaric, 

 growing from the roof or sides, curve their stipes upwardly, as do 

 mushrooms that spring up in a dark night on the side of a sloping 

 bank. T have also shown in the same publication that many plants 

 closely observed by me carry on their curving operations by night 

 rather than in the light of day. So in regard to the thought that 

 the operations of plant life are carried on for individual good — the 

 great weapon in the battle for life among modern hynotheses of 

 evolution, this must be ti'ue to a limited extent. In the case of 

 the Magnolia acuminata herewith illustrated (Plate XVI), we can 

 see that if the curvings of the young shoots continued witliout any 

 change in the original direction of the main laterals, the head of 

 the tree would become as round as a cabbage and the interior 

 branches would be smothered out. The declination iu time gives 

 scope to the young growth, and even tlie final uprising of the 

 branch toward its apex is. still kept within regulation distance of 

 its fellows. In the Fir and Spruce the self-utility of the curvatures 



