MARESTAIL (Conyza canadensis)
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How to identify Marestail/Horseweed (Conyza
How to identify Marestail/Horseweed (Conyza canadensis)
This is marestail or horseweed, a member of the family Asteraceae that is native to North America which has become an invasive weed in Eurasia and Australia. It is an annual that flowers from mid to late summer.
The plant has several tall, unbranched stems that are each topped with a dense inflorescence. The stems are light green and hairy.
The leaves are simple and narrow, with hairs along their margin and midrib. Both the upper and lower surfaces of the leaves may be sparsely hairy. The lower leaves are slightly toothed, while the leaves on the upper portions of the stems are completely whole along their edges. The leaves are light to dark green in color.
The large, densely branched inflorescence bear many tiny flowers heads. The tiny disk flowers are yellow or white, while the minimally spreading ray flowers are white or pale purple. The flowers will mature into small balls of parachuted seeds.
The plant has a short taproot and only reproduces via seed.
The plant likes full sun and prefers moderately dry soils, but is highly adaptable to various soil conditions. It is common in pastures, meadows, cultivated fields, and gardens.
This plant is a noxious weed in some parts of the US, and is one of the first weeds to have developed a resistance to glyphosate.
Sources:
Weeds of the West, 5th Edition (1991) by Tom D. Whitson, published by the Western Society of Weed Science
University of California Agriculture and Natural Resources IPM – Weed Gallery
http://ipm.ucanr.edu/
United States Department of Agriculture – Plant Database
https://plants.usda.gov
This is marestail or horseweed, a member of the family Asteraceae that is native to North America which has become an invasive weed in Eurasia and Australia. It is an annual that flowers from mid to late summer.
The plant has several tall, unbranched stems that are each topped with a dense inflorescence. The stems are light green and hairy.
The leaves are simple and narrow, with hairs along their margin and midrib. Both the upper and lower surfaces of the leaves may be sparsely hairy. The lower leaves are slightly toothed, while the leaves on the upper portions of the stems are completely whole along their edges. The leaves are light to dark green in color.
The large, densely branched inflorescence bear many tiny flowers heads. The tiny disk flowers are yellow or white, while the minimally spreading ray flowers are white or pale purple. The flowers will mature into small balls of parachuted seeds.
The plant has a short taproot and only reproduces via seed.
The plant likes full sun and prefers moderately dry soils, but is highly adaptable to various soil conditions. It is common in pastures, meadows, cultivated fields, and gardens.
This plant is a noxious weed in some parts of the US, and is one of the first weeds to have developed a resistance to glyphosate.
Sources:
Weeds of the West, 5th Edition (1991) by Tom D. Whitson, published by the Western Society of Weed Science
University of California Agriculture and Natural Resources IPM – Weed Gallery
http://ipm.ucanr.edu/
United States Department of Agriculture – Plant Database
https://plants.usda.gov
5 سال پیش
در تاریخ 1398/07/23 منتشر شده
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