Vernonieae is a tribe

Tribe (biology)

In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...

 of about 1300 species of plants in the aster family

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...

. They are mostly found in the tropics

Tropics

The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately  N and the Tropic of Capricorn in the southern hemisphere at  S; these latitudes correspond to the axial tilt of the Earth...

 and warmer temperate

Temperate

In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...

 areas, both in 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...

 and the Old World

Old World

The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....

. They are mostly herbaceous plant

Herbaceous plant

A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...

s or 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, although there is at least one tree species, Vernonia arborea.

Taxonomy

Vernonieae is considered sister to the tribe Liabeae

Liabeae

Liabeae is a tribe of the Asteraceae native to the Neotropics....

. The tribe originated in southern Africa or Madagascar, and spread to the Americas in at least two different events.

In many works some 80% of the species in this tribe are classified in the genus Vernonia

Vernonia

Vernonia is a genus of about 1000 species of forbs and shrubs in the family Asteraceae. Some species are known as Ironweed. Some species are edible and of economic value. They are known for having intense purple flowers. The genus is named for English botanist William Vernon. There are numerous...

. Other authors, like Harold E. Robinson

Harold E. Robinson

Harold 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...

, divide the tribe into a larger number of small genera.