Symphyotrichum spathulatum var. intermedium
Symphyotrichum spathulatum var. spathulatum
Synonyms: Aster occidentalis var. intermedius, Aster occidentalis var. spathulatum
Western mountain aster as found in a roadside ditch along forest service road #3521, Wenatchee National Forest.................August 13, 2009.
Western aster is an erect perennial wildflower arising 20-100 cm from a creeping rhizome. The herbage is generally smooth or without hairs. The lower stem leaves are oblanceolate in shape and petiolate, and they tend to persist into flowering. They may have entire or serrate margins. The middle and upper leaves are narrower with entire margins and measure from 3-15 cm long and 3-15 mm wide. The leaves tend to be 7-20 times longer than they are wide.
The inflorescence is a corymb or cymose panicle of one to many flower heads about 2.5 cm wide. The involucre is 5-7 mm high with obtuse to acutely tipped bracts. The bracts are green and occasional purple margined. Individual bracts are narrowly linear or linear-oblong with short hairs along the margins. The 20-50 rays are about 6-15 mm long and blue, violet or purple in color.
Variety intermedius is much larger and more branched than variety occidentalis with more flower heads arranged in a leafy-bracteate inflorescence.
Western mountain aster may be found in mountain meadows. Variety intermedius may be found at lower elevations than variety occidentalis.
Western aster is found from British Columbia south through Washington and Oregon to California, and eastward to Idaho and Colorado.
Variety intermedius tends to be found in the eastern portion of the range of the species in eastern Washington and northern Idaho.