Symphyotrichum lanceolatum

Symphyotrichum lanceolatum has a base number of x = 8.[10] Tetraploid, pentaploid, hexaploid, septaploid, and octaploid cytotypes with respective chromosome counts of 32, 40, 48, 56, and 64 have been reported, depending on the infraspecies, as follows:

• S. lanceolatum var. hesperium: 2n = 8x = 64.[4]
• S. lanceolatum var. hirsuticaule: 2n = 4x = 32.[11]
• S. lanceolatum var. interior: 2n = 6x = 48 and 2n = 8x = 64.[12]
• S. lanceolatum var. lanceolatum: 2n = 4x = 32, 2n = 5x = 40, 2n = 6x = 48, 2n = 7x = 56, and 2n = 8x = 64.[13]
• S. lanceolatum var. latifolium: 2n = 8x = 64.[14]

This species may be divided into two subspecies and five varieties, shown here.[3] NatureServe follows this circumscription.[1]

• S. lanceolatum subsp. hesperium
  • S. lanceolatum var. hesperium
• S. lanceolatum subsp. lanceolatum
  • S. lanceolatum var. hirsuticaule
  • S. lanceolatum var. interior
  • S. lanceolatum var. lanceolatum
  • S. lanceolatum var. latifolium

In the case of the subspecies autonyms, sometimes one or the other will be ignored or treated as taxonomic synonyms, as in the case of Plants of the World Online (POWO), for example, shown here:[2]

• S. lanceolatum subsp. lanceolatum
• S. lanceolatum var. hesperium
• S. lanceolatum var. hirsuticaule
• S. lanceolatum var. interior
• S. lanceolatum var. latifolium

Symphyotrichum × salignum growing in Lobnya, Moscow Oblast, Russia

The hybrid of S. lanceolatum var. lanceolatum with S. novi-belgii var. novi-begii, known as Sympyotrichum × salignum, originated in cultivation and is now naturalized in Europe. Hybrids also have been reported with S. boreale, S. laeve, S. lateriflorum, S. puniceum and S. racemosum.[13]

Symphyotrichum lanceolatum is commonly known as panicled aster, white panicled aster, and lance-leaved aster.[3] Other common names include tall white aster,[17] eastern line aster, lance-leaf aster, and white-panicle aster.[18]

Along with other asters that bloom in the fall, Symphyotrichum lanceolatum may be called a Michaelmas daisy. Narrow-leaf Michaelmas daisy is also one of its common names.[18] S. lanceolatum var. interior may be called interior white aster,[19] and S. lanceolatum var. latifolium may be called broadleaf panicled aster.[20] S. lanceolatum var. hesperium common names include western line aster, western willow aster, Wooten's aster, and Siskiyou aster.[21] Another species in the family Asteraceae, Eucephalus glabratus, is also commonly known as Siskiyou aster.[22]

Aster comes from the Ancient Greek word ἀστήρ (astḗr), meaning "star," referring to the shape of the flower. The word "aster" was used to describe a star-like flower as early as 1542 in German physician and botanist Leonhart Fuchs' book De historia stirpium commentarii insignes, Latin for Notable Commentaries on the History of Plants. An old common name for Astereae species using the suffix "-wort" is starwort, also spelled star-wort or star wort. An early use of this name can be found in the same work by Fuchs as Sternkraut, translated from German literally as "star herb" (Stern Kraut).[23]

The specific epithet (second part of the binomial name) lanceolatum is a Latin adjective meaning "lance-shaped."[24] The genus name Symphyotrichum is a combining of Ancient Greek words meaning "junction of hair."[25]

Symphyotrichum lanceolatum is native to much of Canada, the United States, and northwestern Mexico.[3][4] In its native range, it occurs in a wide variety of mostly moist and open habitats, including riparian areas, meadows, and ditches. Distribution and habitat vary among the infraspecies.[13][4]

S. lanceolatum var. lanceolatum is widespread in central and northeastern North America. It is absent in the west and southeast. It grows at 0–900 meters (0–2,950 feet) in stream banks, thicket borders, meadows, fields, and ditches.[13]

S. lanceolatum var. hesperium is a widespread western species native to North America in the Northwest Territories, from British Columbia to Quebec; nearly all the contiguous United States west of the Mississippi River, plus Wisconsin; as well as the Mexican states of Baja California, Sonora and Chihuahua. It grows at 10–2,700 m (30–8,860 ft) on the edges of streams in prairies, wet meadows, open slopes of mountainous pine forests, roadside ditches, and can live in calcareous soil.[4]

S. lanceolatum var. hirsuticaule is native to the northwestern Great Lakes region as well as southeast Manitoba in "mucky soils on glacial deposits," and it can be found at 100–300 m (330–980 ft).[11]

S. lanceolatum var. interior is native to streams in lowlands at 10–400 m (30–1,310 ft) in most of the Great Lakes region of North America as well as the central United States.[12]

S. lanceolatum var. latifolium is a very widespread central and eastern species where grows in thickets, deciduous woods borders, stream banks, and ditches at 0–800 m (0–2,620 ft). It is the only variety native to the southeastern United States.[14]

Symphyotrichum lanceolatum has been introduced and naturalized in many parts of Europe, from Belgium to Serbia to Latvia, where it occurs in disturbed man-made habitats and riparian areas as an invasive species.[26][27][28] As of 2020, it was not on the European Union's List of invasive alien species of Union concern.[29]

Large clone of S. lanceolatum prior to flowering, Ontario, Canada

Several midge species are known to form galls on Symphyotrichum lanceolatum where their larvae can develop, including Rhopalomyia asteriflorae in the flowers or buds resulting in their stunted growth,[34] and Rhopalomyia strobiligemma.[24]

The leaf-blister gall midge Asteromyia paniculata and the fungus Schlerotium asteris have a symbiotic relationship on the leaves in that the fungus gains additional nutrition from the larva and, in turn, gives some shelter to the midge.[34]

Leaf-mining insects known to feed on this species include Sumitrosis inaequalis, Ophiomyia curvipalpis, Phytomyza albiceps, and Microrhopala xerene. Younger instars of gorgone checkerspot caterpillars (Chlosyne gorgone) will feed on S. lanceolatum.[34]

Within its native range, Symphyotrichum lanceolatum has been used by indigenous peoples for a variety of medicinal purposes: S. l. var. hesperium by the Zuni people in the American Southwest for wounds and nosebleed,[38] and S. l. var. lanceolatum by the Iroquois in what is now eastern Canada to treat fever.[39]

Symphyotrichum lanceolatum has been cultivated as an ornamental garden plant and used in the cut flower industry.[40] Cultivar 'Edwin Beckett', developed before 1902, has pale violet-blue ray florets that make a flower head which is about 25 millimeters (1 inch) wide.[41] As of July 2021, it was listed in the Royal Horticultural Society Plant Finder with availability at 3–4 nurseries.[42]