Complimentary 
NEW SERIES VOL. Vll 
NO. 13 
ARNOLD ARBORETUM 
HARVARD UNIVERSITY 
BULLETIN 
OF 
POPULAR INFORMATION 
JAMAICA PLAIN. MASS. JULY II. 1921 
Corylus. American nut-growers are beginning to turn their atten- 
tion to the cultivation of Hazel-nuts (Corylus) and inquiries about these 
plants are now often sent to the Arboretum. Corylus is one of the 
widely distributed genera of the Northern Hemisphere with species in 
eastern and western North America, Japan, Korea, Manchuria, and 
northern and western China, on the Himalayas and the Caucasus, and 
in western Asia and Europe. Most of the species are shrubs, but a 
few of them are trees of considerable size. The following species and 
varieties are established in the Arboretum: Corylus americana, C. Avel- 
lana and its varieties contorta, pendula and quercifolia, C. californica, 
C. chinensis, C. CoLurna, C. heterophylla and its variety sutchuenensis, 
C. maxima and its var. atropurpurea, C. rostrata, C. Sieboldiana and 
its var. mandschurica, and C. tibetica. Three of these species are 
trees, C. Colurna, C. chinensis and C. tibetica. Corylus Colurna, the 
Turkish Hazel or Constantinople Nut, is a native of southeastern Europe 
and Asia Minor, and is a tree sometimes seventy or eighty feet high 
with a tall straight trunk from two to three feet in diameter. This 
handsome tree was cultivated in western Europe as early as the middle 
of the seventeenth century, but it is not known when it was first 
brought to America where it is not common and where so far as the 
Arboretum knows there are no large specimens. The nuts are thick- 
shelled, not often more than half an inch in diameter and enclosed in 
a husk an inch and a half across, open at the end, terminating in num- 
erous, narrow, pointed lobes, and covered with down mixed with gland- 
tipped bristles. Three or four of the fruits are borne together in close 
clusters. Corylus chinensis is a native of central and western China 
49 
