BULLETIN NO. 48. 
Several of the Oaks of eastern Asia are established in the Arbore- 
tum, including all the species of northern Japan, eastern Siberia, 
northern Korea and northern China. In addition to these there is a 
large collection of young plants raised from Wilson’s seeds collected 
in western China. These are growing rapidly and appear to be per- 
fectly hardy, but their relationship and names have not yet been de- 
termined. There are many evergreen Oaks in southern Japan and 
southern China, but none of these are hardy in our northern states- 
where only the species with deciduous leaves can be grown. These 
all belong to the White Oak Group, that is they are species which 
mature their acorns in one season, all the Black Oaks, which require 
two seasons for the development of their fruit, being found only in 
America. There are six Japanese Oaks in the Arboretum; the largest 
and most valuable of these are Quercus grosseserrata and Q. crispula . 
These two trees under favorable conditions sometimes grow in Japan 
to the height of one hundred feet and produce trunks from three to 
four feet in diameter. In central Hokkaido these trees form a con- 
siderable part of the forest growth and their abundance and the value 
of the timber which they produce has already attracted the attention 
of American lumbermen, and it Is probable that Japanese white oak 
timber will become a considerable article of import into the United 
States. The next species, Quercus glandulifera, is perhaps the most 
widely distributed Oak of Japan and the common species of the high 
mountains of the central island at elevations over three thousand feet. 
This is a small tree rarely more than thirty or forty feet tall which 
sometimes begins to bear acorns when not more than a foot high. 
The small leaves somewhat resemble those of one of the American 
Chestnut Oaks. Two Japanese Oaks with narrow leaves, in general 
outline like those of the Chestnut tree, both hardy here, are interest- 
ing on account of their peculiar foliage; the larger of these two trees, 
Q. variabilis, sometimes reaches in Japan the height of eighty feet 
with a trunk three or four feet in diameter. The under surface of 
the leaves is silvery white and the bark is thick and corky. This tree 
is rare in Japan and possibly has been introduced there from China; it 
is common in Korea and in northern and central China. The bark is 
sometimes used as cork and the large, thick cups of the fruit are used 
in the preparation of a black dye and are sold in Chinese markets in 
large quantities. Quercus serrata is a smaller tree with darker bark 
and the leaves are bright green on the two surfaces. The fifth Jap- 
anese Oak in the collection, Q. dentata, is remarkable for the great 
size of the leaves which are often a foot long and eight inches broad, 
obovate in outline and deeply lobed, and for the long, narrow, chest- 
nut brown scales of the cup which nearly encloses the small acorn. 
This is a common tree on the mountains of central Japan and ranges 
far northward and to northern and central China, and, although it 
grows sometimes to a large size, it is rarely a handsome or picturesque 
tree. The dark thick bark is used in tanning leather. There is a 
variety ( pinnatifida ) in the collection with deeply divided leaves. 
The plants of Quercus glandulifera, Q. cris'pula and Q. grosseser- 
rata, although only twenty years old, now produce crops of acorns in 
the Arboretum. This is important for it is extremely difficult to im- 
port acorns from foreign countries in good condition, for they soon lose 
their vitality unless carefully packed in soil or in sphagnum moss. 
For this reason the Oaks of eastern Asia are very rare in American 
