Hello,
Just as you all but gave up on native wildflowers in late summer, these two species have recently started blooming. I found these in Corvallis, along the bike path next to HWY 99W, just north of the wastewater treatment plant.
Hall's Aster blooms later than Douglas' Aster. Also, the flowers are paler and smaller and have fewer phyllaries (the little bracts beneath the ray petals).
I made a full comparison in Sept. 2021 (with photos), between Hall's and Douglas' Aster
Gairdner's Yampah (Perideridia gairdneri). I'm calling this P. gairdneri instead of P. oregana because the fruits are wider than long. It looks like Queen Anne's Lace at a glance. I made a full comparison in Aug 2023 (with photos), between Yampah & Queen Anne's Lace.
Don Boucher
Corvallis