Heliantheae

Heliantheae
Sunflowers display bright yellow colors.
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Asterales
Family:	Asteraceae
Tribe:	Heliantheae Cassini, 1819
Subtribes
See text.
Diversity
About 190 genera and 2500 species

The tribe Heliantheae is the most familiar tribe of the sunflower family (Asteraceae). The name is derived from the genus Helianthus, which is Latin for sun flower. The Heliantheae is the third largest tribe in the sunflower family, with some 190 genera and nearly 2500 recognized species. Only the tribes Senecioneae and Astereae are larger. Most genera and species are found in North America and South America, particularly in Mexico. A few genera are pantropical.

Most Heliantheae are herbs or shrubs, but there are some that grow to the size of small trees. Leaves are usually hairy and arranged in opposite pairs. The anthers are usually blackened.

Uses

Commercially important plants in the Heliantheae include sunflower and jerusalem artichoke. Many garden flowers are also in this group, such as Coreopsis, Cosmos, Echinacea, Rudbeckia, and Zinnia.

In addition to the benefits brought by the group, there are also problematic weeds. Species of Ambrosia (ragweed) produce large quantities of pollen. Each plant is reputed to be able to produce about a billion grains of pollen over a season, and the plant is wind-pollinated. It is highly allergenic, as the greatest pollen allergen of all pollens, and the prime cause of hayfever.

Subtribes and representative genera

The traditional circumscription of the Heliantheae arises from Cassini's 19th century classification of the Asteraceae. This broad Heliantheae has been divided by some authors into smaller tribes: Bahieae, Chaenactideae, Coreopsideae, Helenieae, Heliantheae sensu stricta, Madieae, Millereae, Perityleae, Polymnieae, and Tageteae. The Heliantheae is closely related to the Eupatorieae, although the precise relationships are a matter of ongoing research.

In his 1981 revision of the Heliantheae, Harold Ernest Robinson divided the group into 35 subtribes:

• Ambrosiinae (includes: ragweed)
  
• Baeriinae
  
• Chaenactidinae
  
• Clappiinae
  
• Clibadiinae
  
• Coreopsidinae (includes: Coreopsis, Cosmos)
  
• Coulterellinae
  
• Desmanthodiinae
  
• Dimeresiinae
  
• Ecliptinae
  
• Engelmanniinae (includes: rosinweed)
  
• Enhydrinae
  
• Espeletiinae
  
• Fitchiinae
  
• Flaveriinae
  
• Gaillardiinae
  
• Galinsoginae (includes: Hidalgoa)
  
• Guardiolinae
  
• Helianthinae (includes: sunflowers)
  
• Heptanthinae
  
• Hymenopappinae
  
• Jaumeinae
  
• Lycapsinae
  
• Madiinae (includes: tarweeds, Hawaiian silverswords)
  
• Marshalliinae
  
• Melampodiinae
  
• Milleriinae
  
• Montanoinae
  
• Neurolaeninae
  
• Pectidinae
  
• Peritylinae
  
• Pinillosinae
  
• Polymniinae
  
• Rudbeckiinae (includes: Echinacea, Rudbeckia)
  
• Varillinae
  
• Zaluzaniinae
  
• Zinniinae (includes: Zinnia)
  

See also: List of Asteraceae genera

References

• Bremer, Kåre. (1994). Asteraceae: Cladistics & Classification. Portland, OR: Timber Press. ISBN 0-88192-275-7.
• Robinson, Harold Ernest. (1981). A Revision of the Tribal and Subtribal Limits of the Heliantheae (Asteraceae). Smithsonian Contributions to Botany: 51.
• Strother, John L. (1991). Taxonomy of Complaya, Elaphandra, Iogeton, Jefea, Wamalchitamia, Wedelia, Zexmenia, and Zyzyxia (Compositae - Heliantheae - Ecliptinae). Systematic Botany Monographs: 33. ISBN 0-912861-33-9.