[Asters: The Genera Canadanthus, Eucephalus, Eurybia, Oreostemma, and Symphyotrichum in Mt. Adams Country]

Western Mountain Aster, Western Aster

Symphyotrichum spathulatum

Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum

Flower head of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum)

The photo above shows a close-up of the flower head of western mountain aster as found in a vernally moist area along Road K1000 to the east of the Mount Adams Highway.........June 17, 2006.


Stem leaf of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum)The photo at right illustrates the mid to upper stem leaves of western aster as found in prairie alongside Lakeside Road in Conboy Lake National Wildlife Refuge.........August 10, 2007. Note the narrow leaves which taper gradually to a point. They also are sessile to short-petiolate.
Characteristics:

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.

 


Involucral bracts of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum)


Habitat:

Western aster may be found in mountain meadows and in riparian areas along streams and rivers. Variety intermedius may be found at lower elevations than variety occidentalis.


Range:

Western mountain aster is found from British Columbia south through Washington and Oregon to California, and eastward to Idaho and Colorado.


Inflorescence of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum) - Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum)

The photo at left shows the upper stem and inflorescence of western mountain aster as found along Road K1000 on the southeastern slopes of Mt. Adams.........June 17, 2006. Note the narrow bracts tapering gradually to a fairly sharp point. The photo at right shows a portion of the inflorescence of western mountain aster as seenin wetlands along the Willard Springs Trail at Conboy Lake NWR.........September 17, 2017.

Stem leaf of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum)
One of the larger (and wider) stem leaves of western mountain aster as found along Road K1000 on the southeastern slopes of Mt. Adams.........June 17, 2006.

Involucral bracts of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum) - Involucral bracts of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum) - Flower head of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum) - Stem leaves of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum)

The photos above show various views of western mountain aster as seen in prairie alongside Lakeside Road in Conboy Lake NWR..........August 10, 2007.


Stem leaf of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum) - Involucral bracts of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum) - Flower heads of Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum)

The 3 photos above show close-ups of western mountain aster as seen in Swampy Meadows on the western slopes of Mt. Adams........September 6, 2008.


Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum) - Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum)

Western mountain aster as seen in wetlands at Willard Springs, Conboy Lake National Wildlife Refuge......October 23, 2023.

Western Mountain Aster, Western Aster: Symphyotrichum spathulatum (Synonyms: Aster occidentalis, Aster occidentalis var. fremontii, Aster occidentalis var. intermedius, Aster occidentalis var. occidentalis, Aster spathulatus, Aster spathulatus var. spathulatus, Aster vallicola, Symphyotrichum spathulatum var. intermedium, Symphyotrichum spathulatum var. spathulatum, Symphyotrichum spathulatum var. yosemitanum)

Western mountain aster as seen in wetlands at Willard Springs, Conboy Lake National Wildlife Refuge.......August 26, 2018. This is former var. intermedius with a more branched inflorescence, more flower heads and narrower stem leaves.
Paul Slichter