the plant family Salicaceae, characterized by deciduous trees and shrubs having simple, alternate leaves, hairy catkins of male and female flowers on separate plants, and capsular fruit, and including the aspen, cottonwood, poplar, and willow.
Examples from the web for willow family
Some foragers are bringing in an off-white pollen, perhaps from the willow family.
Poplars belong to the willow family and resemble willows in flower and fruit characteristics.