Scientific Name Synonyms
- Conyza canadensis is an annual with a long taproot and one or more stems arising from a basal rosette, normally about 3.3 ft. (1 m) tall.
- Leaves are up to 4 in. (10 cm) long and about 0.4 in. (1 cm) wide with some shallow teeth, green with some scattered hairs. Leaf margins ciliate and with longer hairs towards the base of the leaf.
- Flower heads are very numerous on short pedicels, only 0.08-0.12 in. (2-3 mm) in diameter. Disc florets are yellow, contrasting with distinct white ray florets which are 0.02-0.04 in. (0.5-1 mm) long.
- Fruit is light brown and has tufts of white or light brown hair. Seeds 0.04-0.05 in (1-1.3 mm) long with 10-25 off-white pappus hairs, 0.08-0.16 in. (2-4 mm) long.
- Ecological Threat
- Conyza canadensis is a common weed in temperate to tropical regions, preferring disturbed sites such as vacant lots, pastures, and on roadsides. This plant is native to North America.
- University of Massachusetts Amherst Extension
- Flora of North America, www.eFloras.org
- Virginia Tech Weed Identification Guide
- North Carolina State University
- USDA NRCS PLANTS
- USDA ARS GRIN
Images from Bugwood.org