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
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
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
dimorphism
Dimorphism or dimorphic may refer to:
Science
* Dimorphic root systems, plant roots with two distinctive forms for two separate functions
* Sexual dimorphism, a phenotypic difference between males and females of the same species
* Nuclear dimorph ...
of the
cypselae and the fact that each cypsela lacks a
pappus.
/sup> Calenduleae is named for its most economically important genus, '''', 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).
History and phylogeny
Cladistic arrangement of this group of plants has been recognized as far back as Andrea Cesalpino in the 1630s and again by Giulio Pontedera
Giulio Pontedera (7 May 1688 – 3 September 1757) was an Italian botanist
Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who ...
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 is the largest tribe of the Asteraceae, or the sunflower family, comprising over 150 genera and over 3,500 species. Almost one-third of the species in this tribe are placed in the genus ''Senecio''. Its members exhibit probably the w ...
; however, there has been molecular evidence of closer relationships between the Astereae
Astereae is a tribe of plants in the family Asteraceae that includes annuals, biennials, perennials, subshrubs, shrubs, and trees. They are found primarily in temperate regions of the world. Plants within the tribe are present nearly worldwide di ...
and the Calenduleae. This tribe has demonstrated monophyly through chemical analysis of the similar pimerane diterpenes
Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being ...
found within all tested species. '' Osteospermum'' and ''Garuleum
''Garuleum'' is a genus of flowering plants in the sunflower family, native to southern Africa. ''Garuleum'' is one of eight genera of Calenduleae.
Description
The style of disc florets are deeply bifurcate (forked) with linear lobes. They ar ...
'' 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'' is a genus of South American flowering plants in the family Asteraceae.
There is only one known species, ''Eriachaenium magellanicum'', native to southern South America: Argentina (Tierra del Fuego Province, Argentina, Tierra de ...
'' 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 '''' 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''.[Nordenstam, B. and Trift, I. (1999) A phylogenetic Study of the Calenduleae (Asteraceae), XVI International Botanical Congress Session 3.9.6: 3885]
Image gallery
Image:African daisy (Osteospermum sp. 'Pink Whirls').jpg, '' Osteospermum'' "Pink Whirls", a cultivar
Image:Osteospermum_ecklonis1.JPG, '' Dimorphotheca ecklonis'' syn. ''Osteospermum ecklonis''
Image:Chrysanthemoides_monilifera_(Rondevlei_Nature Reserve,_South_Africa).jpg, ''Chrysanthemoides monilifera
''Osteospermum moniliferum'' ''(Chrysanthemoides monilifera)'' is an evergreen flowering shrub or small tree of the Asteraceae (daisy) family that is native to South Africa, such as the Cape Flats Dune Strandveld habitat. Most subspecies have woo ...
''
File:Ringelblume Blüte.jpg, '' Calendula officinalis''
References
External links
*
*
{{Taxonbar, from=Q126356
Asteraceae tribes