Nut Grower's Assn. for 1946. 66-68. 1947. 2. Graves,
Arthur Harmount. A method of controlling the chestnut blight on
partially resistant species and hybrids of _Castanea_. 41st Ann.
Rept. of Northern Nut Growers Assn. 1950. 149-151. 1951. 3. Hauser,
Willibald. Zur Physiologie des Gerbstoffes in der Pflanzenzelle.
III. Protoplasma 27:125-130. 1936-37. 4. Nienstaedt, Hans. Tannin
as a factor in the resistance of chestnut, castanea spp., to the
chestnut blight fungus, _Endothia parasitica_. Phytopathology
43:32-38. 1953. 5. Nierenstein, M. The natural organic tannins. J.
& A. Churchill.

FOOTNOTES:

[Footnote 18: Also of The Division of Forest Pathology, U.S.D.A., Plant
Industry Station, Beltsville, Maryland.]

[Footnote 19: Records furnished by the U.S. Weather Bureau at New Haven,
Conn.]

[Footnote 20: October, 1952, was among the six driest Octobers on
record. These were: 1879, 1892, 1897, 1916 and 1924. From U.S. Weather
Report, New York City.]

Effect of Vermiculite in Inducing Fibrous Roots on Tap-Rooting Tree
Seedlings

HERBERT C. BARRETT[21] and TORU ARISUMI[22]

When seedlings of nut trees and other tap-rooted species are
transplanted from nursery to orchard, the percentage of survival in
often quite low. Perhaps the chief reason for this failure is the marked
and pronounced tendency of most tap-rooted plants to produce little or
no fibrous, branched roots in lieu of the long, straight, and seldom
branched tap roots.

The common practice of undercutting seedlings during the dormant season
to induce a branched root system requires additional labor, and often
results in reduced growth and vigor during the following season. The use
of hardware cloth or other close-meshed wire is effective, but this
method also has the disadvantage of being relatively expensive for the
nurseryman.

Preliminary work carried on during the past two years has shown that
with certain nut trees and other tap-rooted plants, it is possible to
induce fibrous roots by growing such seedlings in vermiculite. The
methods and results of this work are presented in this paper.

Material and Methods

Seeds of black walnut (_Juglans nigra_), Persian walnut (_Juglans
regia_), Chinese chestnut (_Castanea mollissima_), pignut hickory
(_Carya glabra_), shellbark hickory (_Carya laciniosa_), shagbark
hickory (_Carya ovata_), pecan (_Carya illin_), pawpaw (_Asimina
triloba_), and three pe