MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA COLLEGE. 41 
middle; stamens five, exserted; style 3.5 mm. long, two-cleft to above the middle, 
exserted; achene lenticular, 2.5 mm. long, orbicular-oblong or obovoid, conspicuously 
biconvex, black, smooth, shining, or somewhat granular and rather dull. 
(Quebec to British Columbia, south to New Jersey, Minnesota, Colorado and south- 
ern California. Also in Europe and Asia. 
