Canadian Horseweed
Erigeron canadensis L. [Asteraceae]
Himemukashiyomogi (ヒメムカシヨモギ, 姫昔蓬)
Lifeform: weedy annual forb < 1.5 m high
Origin: native to North America (exotic to Japan)
Habitat: roadsides, fields, and meadows
Seed dispersal: wind
Synonyms
Conyza canadensis (L.) Cronquist
Varieties
- var. levis Makino (ケナシヒメムカシヨモギ)
[Syn. Conyza canadensis (L.) Cronquist var. pusilla (Nutt.) Cronquist]
Erigeron canadensis in Hokkaido
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[1] a shoot. [2] close-up of a top. [3] close-up of stem. [4] seeing from the top. [1-3] at a roadside of N23/W2, North Ward, Sapporo, on August 31 2009. [4] a grassland dominated by E. canadensis. [5] close-up of inflorescences. [6] close-up of a stem. [4-6] at a roadside, N22/E3, East Ward, Sapporo, on August 5 2011.
Erigeron canadensis vs E. sumatrensis
| E. canadensis L. (ヒメムカシヨモギ) | E. sumatrensis Retz (オオアレチノギク) | |
| Stem | erect, coarse, long hair | Dense pubescence |
| Leaf | Purple-tinged midvein on rosette. long, coarse hair on leaf margin. Thin, textured leaf | Dense pubescences on both leaf surfaces, in particular, lower one. Thick, velutinous leaf |
| Inflorescence | White ligulates. Many flower heads, rectangular rounds with 2-3 mm Φ | inconspicuous, light-brown ligulates. Larger, liquer (sake) bottle shaped flower heads with 3-4 mm Φ |
References
- Erigeron annuus
- Field training on integrated environmental research 統合環境調査法実習
fauna and flora 出現種リスト - HUSTEP: Plants and Plant communities in Japan
flora list - Nature in the eco-campus of HU - introduction to botany (北大エコキャンパスの自然 - 植物学入門)