''Conyza'' (horseweed, butterweed or fleabane) is a genus of
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...
s in the family
Asteraceae.
They are native to tropical and warm temperate regions throughout the world, and also north into cool temperate regions in
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
and eastern
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
. The
New World
The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...
species of the genus are closely related to ''
Erigeron'' (also known as fleabanes).
[Flora of North America, Horseweed, ''Conyza'' Lessing]
/ref>
The species are annual or perennial
In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...
herbaceous plants, rarely shrubs, growing to 1–2 m tall. The stems are erect, branched, with alternate leaves. The flowers are produced in inflorescence
In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
s, with several inflorescences loosely clustered on each stem.[
Many species of the genus ''Conyza'' are ruderal species and some have been found to be resistant to the herbicide glyphosate.][
]
References
External links
Germplasm Resources Information Network: ''Conyza''
Chinese plant names: ''Conyza''
{{Authority control
Astereae
Asteraceae genera
Ruderal species