noun
: any of various willows that flourish along streams or on alluvial land: as
a. : a much-branched chiefly eastern No. American shrubby willow ( Salix interior ) with lanceolate leaves that are silky when young
b. : a shrubby chiefly western No. American willow ( Salix exigua ) having leaves permanently silky but otherwise resembling the eastern sandbar willow