106 
fruits previously unknown in the Province of Quebec. J.G. Jack’s 
early education was obtained principally in the schools near his 
home and in working on his father’s farm, and later at Cambridge, 
where he spent two winters in studying entomology with Dr. H. A. 
Hagen. He spent the summer of 1883 in the private horticultural 
experiment grounds of Mr. E. S. Carmen, editor of 7’he Rural New 
Yorker, at River Edge, New Jersey, and in 1886 he became con- 
nected with the Arnold Arboretum as an assistant and teacher of 
dendrology. He passed the summers of 1898 and 1900 as an agent 
SILVA OF NORTH AMERICA. 
ROSACE. 
of the Geological Survey and of the Department of Agriculture 
of the United States in exploring the forests of central Colorado 
and of the Big Horn Mountains of Wyoming. In 1900 Mr. Jack 
became instructor in dendrology in the Massachusetts Institute of 
Technology, in addition to his duties in the Arboretum. For many 
years he was a constant contributor to Garden and Forest. In the 
neighborhood of Montreal he has discovered a number of pre- 
viously unknown forms of Crategus. (See Sargent, Rhodora, iii. 
71.) 
EXPLANATION OF THE PLATE. 
Pratt DCLXIX. Cratzeaus CHAMPLAINENSIS. 
CONHA TP WwW dw 
. A flowering branch, natural size. 
. Vertical section of a flower, enlarged. 
A calyx-lobe, enlarged. 
. A fruiting branch, natural size. 
. Cross section of a fruit, natural size. 
Vertical section of a fruit, natural size. 
. A nutlet, side view, enlarged. 
. A nutlet, rear view, enlarged. 
The end of a vigorous shoot, natural size. 
