be infected by _Endothia parasitica_ but the disease
progresses slowly and in some instances results in little harm. The
species has been so recently established in America that practically
nothing is known of its breeding capabilities, but if its
disease-resistance under our climatic conditions is assured it would
appear most hopeful material for replacing our vanishing native species.
Explorers report there is a still more promising chestnut in China,
reaching nearly 100 feet in height under forest conditions, but it has
not yet been secured for trial in this country.

_Castania sativa_, the commercial chestnut of Europe, in many varieties
has long been cultivated in America and for nut production is without
doubt the best of the well-known exotic species. It has no great timber
value, however, and its disease-resistance, though higher than _C.
Americana_, is scarcely great enough to warrant extended use as breeding
material.

The native chinquapin, _Castanea pumila_, in its bush and tree forms
remains as the only promising chestnut not found in the Orient. While
readily inoculated by artificial means, the chinquapins, especially
varieties of the northern bush forms, quite often escape natural
infection, doubtless because of their small size, smooth bark, and less
liability to insect attacks.

Chestnut breeding for nut improvement, chiefly by selection of native
European and Japanese species, has been carried on in several diverse
localities in the United States, with distinctly promising results but
inter-pollinations have also been effected between most species and
varieties, the outcome indicating that rapid improvement along the
desired lines may be expected from crossing the really desirable types.

In 1903 and succeeding years the writer made many careful pollinations
of the native chestnut and the bush chinquapin with European and
Japanese chestnuts in many varieties. Some hundreds of seedlings
resulted, mostly showing a high level of promise as judged by their
initial thrift and vigor of growth, but the appearance in 1907 of the
Endothia disease among the plantings soon put an end to the work with
the native and European chestnuts, as, with scarcely an exception, they
quickly became infected. The crosses of chinquapin and Japan chestnut,
however, showed considerable resistance as a whole, and a number of
individuals have resisted infection until the present time, though
constantly exposed to the disease,