|Flowers and buds|
Description and identification
Erigeron annuus is a herbaceous plant with alternate, simple leaves, and green, sparsely haired stems. Leaves are numerous and large relative to other Erigeron sp., with lower leaves, especially basal leaves, coarsely toothed or cleft, a characteristic readily distinguishing this species from most other Erigeron. Upper leaves are sometimes, not always toothed, but may have a few coarse teeth towards the outer tips.
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Erigeron annuus is native to North America, and is found in 43 of the lower 48 states. It is widespread in many of them, especially in the eastern part of its range, but only occurs in scattered locations in the West and Southernmost parts of its range. It is introduced in Saint Pierre and Miquelon.
Ecology and life cycle
It often grows as an annual but can sometimes grow as a biennial.
Erigeron annuus is a native pioneer species that often colonizes disturbed areas such as pastures, abandoned fields, vacant lots, roadsides, railways, and waste areas. In these habitats it competes, often successfully, with introduced invasive weeds.
Erigeron annuus grows well in full to partial sun, on sites with ample moisture. It is tolerant of a wide range of soil conditions, including gravel and clay. In hot, dry weather, lower leaves often yellow and wither.
Flowers are pollinated by a variety of bees, including Little Carpenter bees, Cuckoo bees, Halictine bees, and Masked bees, as well as flies, including Syrphid flies, bee flies, Tachinid flies, flesh flies, Anthomyiid flies, and Muscid flies. Wasps, small butterflies, and other insects also visit the flowers to a lesser degree, seeking nectar, as well as a few pollen-feeding beetles.
Schinia lynx (Lynx Flower Moth) caterpillars feed on the flowers and seed capsules of Annual Fleabane and other fleabanes, and Lygus lineolaris (Tarnished Plant Bug) sucks the plant juices. Some mammals eat the foliage, flowers, and stems, including sheep, groundhogs, and rabbits.
- Ann Fowler Rhoads and Timothy A. Block, Ill. Ann Anisko, Plants of Pennsylvania, 2nd ed, University of Pennsylvania Press, 2007. pp. 923.
- David M. BRandenburg, Field Guide to Wildflowers of North America, National Wildlife Federation, Sterling Publishing Co., New York, 2010, pp. 150.
-  Annual Fleabane, Erigeron annuus, Illinois Wildflowers, Retrieved Jun. 27, 2014.
- Annual Fleabane, USGS. 3 August 2006, accessed 29 April 2008
- Erigeron annuus (L.) Pers. eastern daisy fleabane, USDA Plants Profile