ern Nut Growers Association
during their 42nd Annual Meeting, held at Urbana in August, 1951. Dr.
Colby is a former president of the Northern Nut Growers Association.

Colby is a seedling of the tree designated as Crath No. 10. The seed was
collected in 1934 from the parent tree near Cosseev, in the Carpathian
mountain region of southern Poland as then constituted, planted in the
nursery of S. H. Graham, Ithaca, New York, and the seedling transplanted
to Urbana, Illinois at the age of two years. It has been fruiting
annually here since 1942, with crops of up to 1-1/4 bushels in recent
years. The accompanying cut shows nuts of the 1951 crop, a little less
than 2/3 natural size. They are thin shelled, like the parent Crath No.
10, well filled with kernels of rich flavor, and are medium in size for
varieties of this species.

[Illustration: Colby walnuts of 1951 crop, showing thin shells and
plump, bright kernels.]

The Colby tree is rather upright in growth, with strong branches, being
the most vigorous among the four hardiest Carpathian seedlings at
Urbana. It was one of two trees on which most catkins survived the
winter of 1950-51, when temperatures at Urbana fell to -19 deg. F. It is
among the earliest Persian walnuts to start growth in spring, blossoming
at Urbana normally in the first half of May. Flowering is protandrous
(male flowers first) but with enough overlap of staminate and pistillate
blossoms to secure a large degree of self-pollination from the abundant
large catkins. Fruit set might be improved, however, by planting nearby
another variety with later staminate catkins.[20] The nuts mature from
the middle to the last of September and have not been seriously affected
by walnut husk maggot or walnut blight at Urbana. The tree is relatively
early in wood maturity, shedding its foliage usually before November, a
characteristic shared by the other hardiest Carpathian seedlings in
Illinois.

Prior to 1952, scions of the Colby walnut (previously designated
Illinois No. 10) were propagated for test by top working on native
eastern walnut (_Juglans nigra_) at two widely separated locations. It
fruited in 1951 at Greensboro, North Carolina, where the early growth
sometimes is injured by spring freezes. (This is common with Carpathian
walnuts in the southeast.) It has survived three winters at Sabula, Iowa
with no cold injury and made unusually vigorous growth there. At both
Urbana and Sabula, it has been compare