Alkali aster is the only annual aster in the Columbia River Gorge. It may be much branched in form and grows from 5-140 cm high. The herbage generally lacks glands or hairs, although the leaf margins may be lined with very small hairs. The leaves are linear to oblanceolate, growing up to 6 cm long and 1 cm wide. The leaves tend to be fleshy in cross section with the lower leaves with short petioles and the mid and upper leaves sessile or subpetiolate.
The several to numerous flower heads are arranged in an open panicle or a terminal spike. The small flower heads have an involucre 5-9 mm high with leafy bracts. The pinkish rays are very short and narrow. They are rarely longer than 2 mm long.
Alkali aster is a wildflower of streambanks, pond and lake margins, and seasonally moist, alkali depressions.
Aster frondosus is found from central Washington south through Oregon (east of the Cascade crest) to California, and eastward through southern Idaho to Idaho and Wyoming.
In the Columbia River gorge, it may be found between the elevations of 0'-600' east of The Dalles, OR.