100 
and engaged in pastoral work in the Presbyterian Church until 
1869, when ill health compelled him to retire. Two years later he 
became a teacher again until 1888, when he found himself in a posi- 
tion to devote his time to the study of botany in which he had been 
interested, as well as in geology and other natural sciences, since 
boyhood. Mr. Hill’s botanical work, which includes the collection 
of a large herbarium and valuable library, has been carried on 
chiefly in the region bordering the western shores of Lake Michi- 
SILVA OF NORTH AMERICA. 
ROSACEA. 
gan, especially in the neighborhood of Chicago, where he has resided 
He has published the results of these studies in 
many papers communicated to the Bulletin of the Torrey Botanical 
Club, The Botanical G‘azette, Garden and Forest, The Naturalist, and 
other technical journals. For the last two or three years Mr. Hill 
for several years. 
has been particularly interested in the genus Crategus, in which he 
has discovered a number of new and interesting forms. 
EXPLANATION OF THE PLATE. 
Puate DCLXVII. CRrat#Gus CORUSCA. 
1. A flowering branch, natural size. 
AD oT wv 
Vertical section of a flower, enlarged. 
. A calyx-lobe, enlarged. 
. A fruiting branch, natural size. 
. Vertical section of a fruit, natural size. 
. Cross section of a fruit, natural size. 
. A nutlet, side view, enlarged. 
