[1] Dating of volcanic tuffs associated with the Latah Formation at White Bird and Sucker Creek Formation at Sucker Creek in 2012 showed an age range from approximately 15.6 million years ago to 14.8 million years ago, placing the species into the Middle Miocene.

[2] Leaves assigned by Wolfe and Tanai to A. whitebirdense were first described in 1932 by Thomas Ashlee as "Viburnum" whitebirdensis.

Edward W. Berry in 1934 described leaves from White Bird as A. florissanti and Platanus dissecta respectively, plus a fruit as A.

[1] Based on the vein structuring in the fruits, Wolfe and Tanai inferred that A. whitebirdense was a probable descendant of A. kenaicum, known from the Oligocene of Alaska.

They also suggested that the late Miocene species A. taggarti was a descendant of A. whitebirdense, based on similarities in the leaves.

Five to seven veins spread from the attachment scar across the nutlet and then converge slightly at the nut tip before extending into the wing.

[1] This led Wolfe and Tanai to suggest that the fruits may have been dispersed by animals and would have fallen straight to the ground, rather than spinning in the wind.