s are likely to
prove hardy to the extent of bearing heavily where winter temperatures
are extremely trying or where soils are not of high grade. A fundamental
principle involving plant ecology, which with reference to planted nut
trees is too often lost sight of, is that, regardless of species, plants
are unlikely to be altogether hardy in any locality where minimum
temperatures of winter are appreciably lower, or growing periods much
shorter, than at the place where the variety in question originated. For
example, it is often assumed that a pecan tree native to southern Texas,
the lowest point of the range of this species in the United States,
should do well in southeastern Iowa, the northernmost point within the
range. Likewise, it is also sometimes assumed that a black walnut
variety originating in Arkansas, Texas or Tennessee should be hardy in
the black walnut belts of New York, Michigan, Wisconsin, Minnesota,
Pennsylvania, or wherever the species is indigenous or has been
successfully transplanted.

There are definite degrees of hardiness which must not be overlooked. A
species or variety may be hardy enough to grow thriftily for many years,
and to make a splendid tree, hundreds of miles north of the latitude at
which it will mature occasional crops; or it may be able to produce
crops that are frequent in occurrence yet indifferent as to character;
or there may be occasional crops of first-class nuts; but good crops of
good nuts are exceedingly rare when the minimum temperatures of winter
or the length of the growing period are appreciably more adverse than in
the locality where the variety originated.

A few illustrations may help to make these points clearer. On the
Experimental Farm of the U. S. Department of Agriculture at Arlington,
Va., directly opposite Washington, on the Potomac, there are five pecan
trees of the Schley variety which originated on the Gulf coast of
Mississippi. These trees have grown splendidly since being planted more
than 20 years ago. They blossomed and set nuts more or less regularly
after they were about eight or ten years of age, but it was only in the
eighteenth year that a season was late enough in fall for a single nut
to mature. Another case is afforded by a pecan seedling, probably from
Texas, called to the writer's attention by Dr. W. C. Deming, Hartford,
Conn., which stands near the outskirts of that city. This is a large,
beautiful tree. It rarely sets crops of nuts, and wh