Chromolaena
Encyclopedia
Chromolaena is a genus of about 165 species of perennials
and shrub
s in the aster family, Asteraceae
. The name is derived from the Greek
words χρῶμα (chroma), meaning "color," and λαινα (laina), meaning "cloak." It refers to the colored phyllaries
of some species. Members of the genus are native to the Americas
, from the southern United States
to South America
(especially Brazil
). One species, Chromolaena odorata
, has been introduced
to many parts of the world where it is considered a weed
.
The plants of this genus were earlier taxonomically classified under the genus Eupatorium
, but are now considered to be more closely related to other genera in the tribe Eupatorieae
.
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
and shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s in the aster family, Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
. The name is derived from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
words χρῶμα (chroma), meaning "color," and λαινα (laina), meaning "cloak." It refers to the colored phyllaries
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
of some species. Members of the genus are native to the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
, from the southern United States
Southern United States
The Southern United States—commonly referred to as the American South, Dixie, or simply the South—constitutes a large distinctive area in the southeastern and south-central United States...
to South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
(especially Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
). One species, Chromolaena odorata
Chromolaena odorata
Chromolaena odorata is a species of flowering shrub in the sunflower family, Asteraceae. It is native to North America, from Florida and Texas to Mexico and the Caribbean, and has been introduced to tropical Asia, west Africa, and parts of Australia. Common names include Siam Weed, Christmas Bush,...
, has been introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
to many parts of the world where it is considered a weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
.
The plants of this genus were earlier taxonomically classified under the genus Eupatorium
Eupatorium
Eupatorium is a genus of flowering plants in the aster family, Asteraceae, containing from 36 to 60 species depending on the classification system. Most are herbaceous perennial plants growing to 0.5–3 m tall. A few are shrubs. The genus is native to temperate regions of the Northern Hemisphere....
, but are now considered to be more closely related to other genera in the tribe Eupatorieae
Eupatorieae
Eupatorieae is a tribe of over 2000 species of plants in the aster family. Most of the species are native to tropical, subtropical, and warm temperate areas of the Americas, but some are found elsewhere...
.
Selected species
- Chromolaena bigelovii (A.GrayAsa Gray-References:*Asa Gray. Dictionary of American Biography. American Council of Learned Societies, 1928–1936.*Asa Gray. Encyclopedia of World Biography, 2nd ed. 17 Vols. Gale Research, 1998.*Asa Gray. Plant Sciences. 4 vols. Macmillan Reference USA, 2001....
) R.M.King & H.Rob.Harold E. RobinsonHarold Ernest Robinson is an eminent botanist and an entomologist.-Career:Dr. Robinson's systematic knowledge encompasses many groups of plants and even some insects. But his real specialty is the sunflower family and the bryophytes...
– Bigelow's Thoroughwort - Chromolaena borinquensis (Britt.) R.M.King & H.Rob. – Limestone Thoroughwort
- Chromolaena corymbosa (Aubl.) R.M.King & H.Rob. – Caribbean Thoroughwort
- Chromolaena frustrata (B.L.Rob.Benjamin Lincoln RobinsonBenjamin Lincoln Robinson was an American botanist.-External links:*...
) R.M.King & H.Rob. – Cape Sable Thoroughwort - Chromolaena geraniifolia (Urb.) R.M.King & H.Rob. – Geraniumleaf Thoroughwort (Puerto RicoPuerto RicoPuerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
) - Chromolaena hirsuta (Hook. & Arn.) R.M.King & H.Rob.
- Chromolaena impetiolaris (Griseb.) Nicolson
- Chromolaena integrifolia (Bertero ex Spreng.) R.M.King & H.Rob.
- Chromolaena ivifolia R.M.King & H.Rob. – Ivyleaf Thoroughwort
- Chromolaena macrodon (DC.) Nicolson
- Chromolaena odorataChromolaena odorataChromolaena odorata is a species of flowering shrub in the sunflower family, Asteraceae. It is native to North America, from Florida and Texas to Mexico and the Caribbean, and has been introduced to tropical Asia, west Africa, and parts of Australia. Common names include Siam Weed, Christmas Bush,...
(L.) R.M.King & H.Rob. – Jack in the Bush - Chromolaena oteroi (Monachino) R.M.King & H.Rob. – Mona Island Thoroughwort
- Chromolaena sinuata (Lam.) R.M.King & H.Rob. – Wavyleaf Thoroughwort
- Chromolaena squalida (DC.) R.M.King & H.Rob.
- Chromolaena trigonocarpa (Griseb.) R.M.King & H.Rob.