. All have been attacked by blight, the most
promising one only this spring, after thirteen years of resistance to
this virulent disease. All the hybrids carrying blood of native or
European chestnuts were quickly killed, but those with the Japanese
species as a pollen parent are still growing vigorously and bearing
well, though considerably disfigured by blight.

Of the various species used the native sweet chestnut, _Castanea
Americana_, and the European, _C. vesca_, appear entirely useless in
breeding for disease resistance, as the hybrids are destroyed by the
blight fungus as soon as, or even before, they reach bearing age. The
tall, or tree, forms of native chinquapin, sometimes grouped under the
botanical name of _Castanea arborea_ but which appear to be only natural
hybrids between the sweet chestnut and the bush chinquapin, may also be
regarded as useless for the purpose. The hybrid progeny show slight
powers of recuperation but, in our plantings, do not sufficiently
recover to make useful trees. The Rush chinquapin sometimes resists
infection under natural conditions for several years but quickly
succumbs when attacked, but its hybrid seedlings develop practically no
resistance. The common bush or dwarf chinquapin, _Castanea pumila_,
widely distributed over the Atlantic States, is not as readily infected
by blight as the chestnut, many individuals under cultivation and in the
wild resisting attack for an indefinite time, while the creeping species
of Florida and South Georgia, _C. alnifolia_, appear practically immune
in nature but succumb to artificial inoculation with the blight virus
The smooth bark and shrubby forms of these dwarf chinquapins probably
account to a very great extent for the limited damage caused by blight
under natural conditions.

Next in degree of resistance comes the wooly-twigged Chinese chestnut,
_C. molissima_. There are established at Bell Experiment Plot over nine
hundred Molissima trees grown from nuts collected near Tien-Tsin, China,
in 1911. These trees in their eighth year of growth have borne excellent
nuts, rather larger than those of our native species, in some quantity
for three successive years though, owing to extensive locust injury last
season, there is practically no crop this year. The trees average twelve
or more feet high and are thrifty growers when not too greatly afflicted
by blight. No summary of disease injury has been taken, but probably
over 80 per cent of the