1915] * BALL—WILLOWS 53 
The exact identity of this plant is uncertain. The descriptions given by 
NUTTALL of his seven new species in § LONGIFOLIAE are often meager. Fre- 
quently, too, there is very little difference in the series of characters assigned 
3-—Salix fluviatilis (?) Nutt.: portions of two fruiting twigs, collected by 
"ke in cVieins County, Oregon, July, 1875 (specimens in Bebb Herb., Field 
Museum of Natural History; left FBb 6575; right, FBb 6576); nat. size. 
to two or more separate species. There is some confusion, also, in the types 
and cotypes of some species. The plant here provisionally referred to S. 
