Calenduleae
Encyclopedia
Calenduleae is a flowering plant
tribe of the family Asteraceae
. Calenduleae has been widely recognized since Alexandre de Cassini
in the early 19th century. There are eight genera and over 110 species, mostly found in South Africa
.
It is a relatively stable clade
of the Asteraceae, with minor alterations. The tribe also occurs in Southwest Asia, some Atlantic islands, other portions of Africa and Europe, with non-native occurrences in the US, Australia, and New Zealand. However, three new species within the tribe have been discovered as recently as 2003.
of the cypselae and the fact that each cypselae lacks a pappus
.[2] Calenduleae is named for its most economically important genus, Calendula
, known in homeopathic remedies and as a common ornamental. Other genera from Calenduleae produce ornamentals as well, including Osteospermum
and Dimorphotheca
(see Asteraceae
for a more general description).
in the 1630s and again by Giulio Pontedera
in the 1720s, but the official nomenclature arose after Cassini's work within the family. Early 20th-century botanists placed this tribe as sister to the Senecioneae
; however, there has been molecular evidence of closer relationships between the Astereae
and the Calenduleae. This tribe has demonstrated monophyly
through chemical analysis of the similar pimerane diterpenes found within all tested species. Osteospermum
and Garuleum
share the highest number of identical chemical signatures, indicating close phylogenetic relationship and a more recent divergence than other genera of the tribe. One of the newly discovered Osteospermum has provided evidence of a link between Osteospermum and Chrysanthemoides.
There have been some rearrangements of the Calenduleae tribe. Eriachaenium
was originally lumped with the Calenduleae but has since been removed. Its placement remains uncertain, although it is now hypothesized to belong to the Cichorioideae
. The genus Castalis
has been folded into Osteospermum. One recent analysis of the Calenduleae made several phylogenetic discoveries, including:
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
tribe of the 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...
. Calenduleae has been widely recognized since Alexandre de Cassini
Alexandre de Cassini
Count Alexandre Henri Gabriel de Cassini was a French botanist and naturalist, who specialised in the sunflower family ....
in the early 19th century. There are eight genera and over 110 species, mostly found in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
.
It is a relatively stable clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of the Asteraceae, with minor alterations. The tribe also occurs in Southwest Asia, some Atlantic islands, other portions of Africa and Europe, with non-native occurrences in the US, Australia, and New Zealand. However, three new species within the tribe have been discovered as recently as 2003.
Description
Plants in Calenduleae vary from herbs to shrubs and usually exhibit showy flower heads. The defining characteristics separating members of this tribe from others within the family are a dimorphismPolymorphism (biology)
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
of the cypselae and the fact that each cypselae lacks a pappus
Pappus (flower structure)
The pappus is the modified calyx, the part of an individual disk, ray or ligule floret surrounding the base of the corolla, in flower heads of the plant family Asteraceae. The pappus may be composed of bristles , awns, scales, or may be absent. In some species, the pappus is too small to see...
.[2] Calenduleae is named for its most economically important genus, Calendula
Calendula
Calendula , pot marigold, is a genus of about 12–20 species of annual or perennial herbaceous plants in the daisy family Asteraceae, native to the area from Macaronesia east through the Mediterranean region to Iran...
, known in homeopathic remedies and as a common ornamental. Other genera from Calenduleae produce ornamentals as well, including Osteospermum
Osteospermum
Osteospermum is a genus belonging to the Calenduleae, one of the smaller tribes of the sunflower family .Osteospermum used to belong to the genus Dimorphotheca, but only the annual species remain in that genus; the perennials belong to Osteospermum. The genus Osteospermum is also closely related...
and Dimorphotheca
Dimorphotheca
Dimorphotheca, commonly called Cape marigold, is one of eight genera of the Calenduleae, with a center of diversity in Southern Africa. Some species can hybridize with Osteospermum, and crosses are sold as cultivated ornamentals...
(see 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...
for a more general description).
History and phylogeny
Cladistic arrangement of this group of plants has been recognized as far back as Andrea CesalpinoAndrea Cesalpino
Andrea Cesalpino was an Italian physician, philosopher and botanist....
in the 1630s and again by Giulio Pontedera
Giulio Pontedera
Giulio Pontedera was an Italian botanist. He was professor of botany at Padua, and director of the botanical garden there. Although he rejected Carolus Linnaeus' system, Linnaeus was a correspondent of Pontedera's, and named the genus Pontederia after him.-References:...
in the 1720s, but the official nomenclature arose after Cassini's work within the family. Early 20th-century botanists placed this tribe as sister to the Senecioneae
Senecioneae
Senecioneae is the largest tribe of the Asteraceae, or the sunflower family, comprising approximately 150 genera and 3,000 species. Almost one-third of the species in this tribe are placed in the genus Senecio...
; however, there has been molecular evidence of closer relationships between the Astereae
Astereae
Astereae is a tribe of plants in the family Asteraceae that includes annuals, biennials, perennials, subshrubs, shrubs and trees. Plants within the tribe are present nearly worldwide divided into 170 genera and more than 2,800 species...
and the Calenduleae. This tribe has demonstrated monophyly
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...
through chemical analysis of the similar pimerane diterpenes found within all tested species. Osteospermum
Osteospermum
Osteospermum is a genus belonging to the Calenduleae, one of the smaller tribes of the sunflower family .Osteospermum used to belong to the genus Dimorphotheca, but only the annual species remain in that genus; the perennials belong to Osteospermum. The genus Osteospermum is also closely related...
and Garuleum
Garuleum
Garuleum is one of eight genera of Calenduleae, with its center of diversity in Africa.Some species include:*Garuleum bipinnatum Less.*Garuleum woodii Schinz *Garuleum album S. Moore *Garuleum coeruleum Steud....
share the highest number of identical chemical signatures, indicating close phylogenetic relationship and a more recent divergence than other genera of the tribe. One of the newly discovered Osteospermum has provided evidence of a link between Osteospermum and Chrysanthemoides.
There have been some rearrangements of the Calenduleae tribe. Eriachaenium
Eriachaenium
Eriachaenium is a genus of flowering plants in the daisy family....
was originally lumped with the Calenduleae but has since been removed. Its placement remains uncertain, although it is now hypothesized to belong to the Cichorioideae
Cichorioideae
Cichorioideae is a subfamily of the family Asteraceae of flowering plants. Familiar members of Cichorioideae include lettuce, dandelions and Gazanias. The subfamily comprises about 240 genera and about 2900 species...
. The genus Castalis
Castalis
Castalis is a genus of flowering plants in the daisy family....
has been folded into Osteospermum. One recent analysis of the Calenduleae made several phylogenetic discoveries, including:
- the Osteospermum section Blaxium is now placed in the genus Dimorphotheca
- the subgenus Tripteris was separated from Osteospermum
- the genus Oligocarpus was separated from Osteospermum
- Osteospermum sanctae-helenae, endemic to St. Helena, now belongs to Oligocarpus.