Shaler.] 
264 
[March 4, 
flight of these species, in a single season, for the distance of many 
hundred miles. It is possible indeed for such seeds to be carried 
in a north or south direction for a thousand miles in one or two 
days. Where the seeds are of somewhat larger size of such bulk 
or weight as would prevent them from being borne by the winds, 
or accidentally attached to the bodies of water fowl, they may be 
carried, though less far still over wide areas, in a rapid manner, 
in the crops of birds ; beech nuts, for instance, may be thus con- 
veyed by a passenger pigeon for a hundred miles or more without 
being so far affected by digestion as to lose their vitality ; the 
bird being then killed by accident the seeds may be cast upon 
the ground. It may even happen that the seed may pass, as 
is sometimes the case with those of fruits, unharmed through 
the digestive canal and be voided with the excrement and thus 
find a chance to take root. 
It is far otherwise with the nuts of our large seeded trees. 
Those of our walnuts and hickories are not liable to be borne to 
any distance by the ordinary winds ; they are not taken in an un- 
broken form into the digestive tract of animals and they are man- 
ifestly incapable of being accidentally conveyed into condition of 
attachment to the feet or feathers of birds. The only methods in 
which they can secure distant carriage appears to me to be as 
follows: They are readily conveyed by streams, and may thus 
be widely disseminated along the paths of the principal rivers 
throughout the region where the climatal conditions of the area 
through which the stream passes make the country fit for their 
occupancy. In a region traversed by tornadoes it seems likely 
that the seed, even the largest size, may be conveyed throughout 
the range of the whirlwind’s path. From observations made on 
the effect of carriage of these tornadoes in the Mississippi valley 
it seems likely that a single meteor of this description might well 
effect the transportation of walnuts for the distance of thirty 
miles or more. 
In the case of such plants as the walnuts and other equally 
large seeded trees the only method of diffusion, besides those 
above indicated, which depend upon other agencies than the plant 
itself, consists in the habit of certain rodents, particular the 
squirrels, which carry seed in their mouths or cheek pouches for 
a certain distance from the parent tree. From my own observa- 
tion on this nut carrying habit I am disposed to believe that rare- 
