Anthemis arvensis L.
Keys to Identification
- Has no odor
- Small daisy-like flowers
This information courtesy of the Colorado Natural Areas Program
Family: Asteraceae (Sunflower)
Other Names: scentless chamomile, chamomile, mayweed
USDA Code: ANAR6
Legal Status: Colorado Noxious Weed List B
Growth form: Forb
Flower: Flowers are 3/4 in wide and are borne at the ends of branched stems. Flowers resemble daisies with white ray flowers and yellow disc flowers. Mid-May-Sept.
Seeds/Fruit: Seeds (achenes) are dark brown and grooved.
Leaves: Leaves are alternate and finely dissected.
Stems: Mature plants are 10-30 in tall. Stems are erect, smooth, and highly branched above.
Roots: Dense fibrous root system.
Exotics: scentless chamomile (Matricaria perforata) is common on the western slope, and is sometimes confused with corn chamomile (Anthemis arvensis) or mayweed chamomile (Anthemis cotula). Corn chamomile is almost identical to mayweed chamomile but can be identified by its lack of odor.
Natives: The native Hymenopappus newberryi has few stem leaves, and is perennial.
Agricultural: Corn chamomile can reduce crop production. It is considered unpalatable to livestock and its feed value is poor (Woo et al. 1991).
Habitat and Distribution
General requirements: Corn chamomile is commonly associated with newly disturbed habitats. It is found along roadsides, ditches, in urban areas, waste places, cultivated fields, and pastures. It can grow in a wide range of soils but seems to prefer moist, poorly drained soils. Corn chamomile prefers moist areas and increases in abundance during years of above average precipitation.
Distribution: Not yet widespread in Colorado.
Historical: Corn chamomile is a native of Europe that was introduced into North America as an ornamental or seed contaminant.
Corn chamomile germinates readily in the spring and fall. It has a dense, fibrous root system, which spreads rapidly during wet periods. Late summer and fall-germinated seedlings may overwinter as rosettes. In the spring, bolting commences with the elongation of the central stem. Overwintering plants flower in mid-May and spring germinated seedlings flower in June. Flowering stops after a killing frost, usually in October.
Mode of reproduction: Reproduces primarily by seeds. Occasionally, basal shoots that are lying along the ground surface will develop adventitious roots along the contact surface (Woo et al. 1991).
Seed production: Corn chamomile is a prolific seed producer and can produce up to 960,000 seeds per plant.
Seed bank: Seed may remain viable in the soil for 4-6 years.
Colorado Natural Areas Program. 2000. Creating an Integrated Weed Management Plan: A Handbook for Owners and Managers of Lands with Natural Values. Colorado Natural Areas Program, Colorado State Parks, Colorado Department of Natural Resources; and Division of Plant Industry, Colorado Department of Agriculture. Denver, Colorado. 349 pages.
USDA, NRCS. 2005. The PLANTS Database, Version 3.5 (http://plants.usda.gov). Data compiled from various sources by Mark W. Skinner. National Plant Data Center, Baton Rouge, LA 70874-4490 USA
Whitson, T.D.(ed.), L.C. Burrill, S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee, R. Parker. 1996. Mayweed chamomile. Weeds of the West. Western Society of Weed Science, in cooperation with the Western United States Land Grant Universities Cooperative Extension Services, Newark CA. pg. 55.
Woo, S.L., A.G. Thomas, D.P. Peschken, G.G. Bowes, D.W. Douglas, V.L. Harms, and A.S. McClay. 1991. The biology of Canadian weeds. 99. Matricaria perforata Merat (Asteraceae). Canadian Journal of Plant Science 71: 1101-1119.