Siskiyou aster

(Symphyotrichum lanceolatum ssp. hesperium)



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Symphyotrichum lanceolatum ssp. hesperium is a subspecies of the Symphyotrichum lanceolatum plant, commonly known as Siskiyou aster or western aster. This subspecies is native to western North America, particularly in California, Oregon, and Washington.

Symphyotrichum lanceolatum ssp. hesperium prefers full sun to partial shade and well-draining soil. It is often found in meadows, open woodlands, and along roadsides. In the mountain west it is also found in cordilleras.


This subspecies is differentiated from ssp. lanceolatum by characteristics of the inflorescence. The flower heads are usually subtended by larger, broader, leaf-like bracts. The outer bracts of the involucre (phyllaries) are longer, more than two-thirds the length of the inner ones.


Distribution Map



3, 4, 28, 29, 30.

  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  


Asterales (sunflowers, bellflowers, fanflowers, and allies)  


Asteraceae (sunflowers, daisies, asters, and allies)  
  Subfamily Asteroideae  
  Supertribe Asterodae  
  Tribe Astereae (asters and allies)  
  Subtribe Symphyotrichinae  
  Genus Symphyotrichum (American asters)  
  Subgenus Symphyotrichum (common American asters)  
  Section Symphyotrichum (bushy, eastern, heart-leaved, and old field asters)  
  Subsection Dumosi (bushy asters)  
  Species Symphyotrichum lanceolatum (panicled aster)  



This and other asters were formerly place in the genus Aster. That genus was problematic, in that it did not include just one common ancestor with all of its lineal descendants and no others – it was not monophyletic. In 1994, the genus Symphyotrichum was resurrected to include most North American asters formerly in the genus Aster.


Subordinate Taxa


Siskiyou aster (Symphyotrichum lanceolatum var. hesperium)




Aster hesperius


Common Names


Siskiyou aster

western panicled aster

white panicle aster










Modified leaf at the base of a flower stalk, flower cluster, or inflorescence.



A whorl of bracts beneath or surrounding a flower or flower cluster.



An individual bract within the involucre of a plant in the Asteraceae family.

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