Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Astereae
Genus: Conyza
Species: C. canadensis
Binomial name: Conyza canadensis
Synonyms: Erigeron canadensis
Common name: Canadian Horseweed, Horseweed, Canadian Fleabane, Coltstail, Marestail and Butterweed
Conyza canadensis (formerly Erigeron canadensis L.) is an annual plant native throughout most of North America and Central America. It is an annual plant growing to 1.5 m tall, with sparsely hairy stems. The leaves are slender, 2–10 cm long and up to 1 cm broad, with a coarsely toothed margin. The flowers are produced in dense inflorescences 1 cm in diameter, with a ring of white or pale purple ray florets and a centre of yellow disc florets. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Bees, flies. It can spread rapidly
Livestock animals seem to ignore the plant because of its bitter taste. It can be found in fields, disturbed sites, waste ground, roadsides, railroads.
The plant was traditionally used to treat many ailments such as diarrhoea, kidney stones, diabetes, and nosebleeds.Many people are allergic to its pollen and can get a reaction just by handling the plant and can cause autumn allergies. The leaves are edible boiled, cooked in rice. In traditional North American herbal medicine, Canada Fleabane was boiled to make steam for sweat lodges, taken as a snuff to stimulate sneezing during the course of a cold and burned to create a smoke that warded off insects. Nowadays it is valued most for its astringency, being used in the treatment of gastrointestinal problems such as diarrhoea and dysentery]. It is said to be a very effective treatment for bleeding haemorrhoids. The whole plant is antirheumatic, astringent, balsamic, diuretic, emmenagogue, styptic, tonic and vermifuge. It can be harvested at any time that it is in flower and is best used when fresh. The dried herb should not be stored for more than a year. The seeds can also be used[. An infusion of the plant has been used to treat diarrhoea and internal haemorrhages or applied externally to treat gonorrhoea and bleeding piles. The leaves are experimentally hypoglycaemic. The essential oil found in the leaves is used in the treatment of diarrhoea, dysentery and internal haemorrhages. It is a uterine stimulant and is also said to be valuable in the treatment of inflamed tonsils plus ulceration and inflammation of the throat. A tea of the boiled roots is used to treat menstrual irregularities. A homoeopathic remedy is made from the plant. It is used in the treatment of haemorrhoids and painful menstruation.
