Willow Astra , also Willow Symphiotrichum , American Willow Astra ( Latin: Symphyótrichum × salígnum ), is a perennial herbaceous plant belonging to the genus Symphiotrichum of the Compositae family.
| Willow Astra |
Botanical illustration from the book of A. Dietrich Flora regni Borussici , 1833-1844 |
| Scientific classification |
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| International scientific name |
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Symphyotrichum × salignum ( Willd. ) GLNesom , 1995 |
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An invasive species of hybrid origin that arose in Europe from the crossing of the native North American species Symphyotrichum lanceolatum (Willd.) GLNesom and Symphyotrichum novi-belgii (L.) GLNesom . The most widespread species in Europe.
Perennial rhizome herbaceous plant (30) 60-100 (130) cm tall. The stem is erect, branched at the top and bearing numerous baskets. In cross section at the top of the stem is ribbed.
The leaves are alternately arranged along the stem, simple, lanceolate to linearly lanceolate, often with a serrated serrated dentate margin, sharp at the end, tapered at the base, slightly widened at the stem and (as a rule, slightly) stem-bearing.
The baskets are numerous, up to 2 cm in diameter, with a cylindrical wrapper made of gravelly pressed pressed grassy leaves, bare or covered with rough pubescence. Reed flowers pale lilac or white, median flowers tubular, yellow.
Symphyotrichum novi-belgii is distinguished by leaves, as a rule, more tightly grasping the stem and having ears, as well as a more loose wrapping of baskets with bent leaves of the outer row. Symphyotrichum lanceolatum is a plant with, as a rule, white reed flowers, with narrow-lanceolate leaves, narrowed into a rather noticeable petiole, not wrapping around the stem.
The species probably originated in Europe in the 18th century. Widely distributed throughout Europe and Western Siberia, also in the Far East and Japan.
