The eudicots, Eudicotidae or eudicotyledons are a monophyletic clade
of flowering plants that had been called tricolpates or non-magnoliid dicots by
previous authors. The botanical terms were introduced in 1991 by evolutionary
botanist James A. Doyle and paleobotanist Carol L. Hotton to
emphasize the later evolutionary divergence of tricolpate dicots from
earlier, less specialized, dicots. The close relationships among flowering
plants with tricolpate pollen grains was initially seen in morphological studies
of shared derived characters. These plants have a distinct trait in their
pollen grains of exhibiting three colpi or grooves paralleling the polar axis.
Later molecular evidence confirmed the genetic basis for the evolutionary
relationships among flowering plants with tricolpate pollen grains and
dicotyledonous traits. The term means "true dicotyledons", as it contains the
majority of plants that have been considered dicots and have
characteristics of the dicots. The term "eudicots" has subsequently been widely
adopted in botany to refer to one of the two largest clades of angiosperms,
monocots being the other. The remaining angiosperms are sometimes referred to as
basal angiosperms or paleodicots, but these terms have not been widely or
consistently adopted, as they do not refer to a monophyletic group.
The other name for the eudicots is tricolpates, a name which refers to the
grooved structure of the pollen. Members of the group have tricolpate pollen, or
forms derived from it. These pollens have three or more pores set in furrows
called colpi. In contrast, most of the other seed plants produce monosulcate
pollen, with a single pore set in a differently oriented groove called the
sulcus. The name "tricolpates" is preferred by some botanists to avoid
confusion with the dicots, a nonmonophyletic group.
Numerous familiar plants are eudicots, including many common food plants,
trees, and ornamentals. Some common and familiar eudicots include members of the
sunflower family such as the common dandelion, the forget-me-not, cabbage
and other members of its family, apple, buttercup, maple, and macadamia. Most
leafy trees of midlatitudes also belong to eudicots, with notable exceptions
being magnolias and tulip trees which belong to magnoliids, and Ginkgo biloba,
which is not an angiosperm. The name "eudicots" is used in the APG
system, of 1998, and APG II system, of 2003, for classification of angiosperms.
It is applied to a clade, a monophyletic group, which includes most of the
dicots. Subdivisions
The eudicots can be divided into two groups: the basal eudicots and the core
eudicots. Basal eudicot is an informal name for a paraphyletic group. The core
eudicots are a monophyletic group. A 2010 study suggested the core eudicots
can be divided into two clades, Gunnerales and a clade called
"Pentapetalae", comprising all the remaining core eudicots.
The Pentapetalae can be then divided into three clades:
the Dilleniaceae a "superrosid" clade consisting of
Saxifragales, Vitales and rosids a "superasterid" clade consisting of
Santalales, Berberidopsidales, Caryophyllales and asterids
Within the core eudicots, the largest groups are the "rosids" and the
"asterids". This division of the eudicots is shown
in the following cladogram: The following is a more detailed
breakdown, showing within each clade some unplaced families and orders:
clade eudicots family Buxaceae [+ family Didymelaceae]
family Sabiaceae family Trochodendraceae [+ family
Tetracentraceae] order Ranunculales
order Proteales clade core eudicots
family Aextoxicaceae family Berberidopsidaceae
family Dilleniaceae order Gunnerales
order Caryophyllales order Saxifragales
order Santalales clade rosids
family Aphloiaceae family Geissolomataceae
family Ixerbaceae family Picramniaceae
family Strasburgeriaceae family Vitaceae
order Crossosomatales order Geraniales
order Myrtales clade eurosids I
family Zygophyllaceae [+ family Krameriaceae]
family Huaceae order Celastrales
order Malpighiales order Oxalidales
order Fabales order Rosales
order Cucurbitales order Fagales
clade eurosids II family Tapisciaceae
order Brassicales order Malvales
order Sapindales clade asterids
order Cornales order Ericales
clade euasterids I family Boraginaceae
family Icacinaceae family Oncothecaceae
family Vahliaceae order Garryales
order Solanales order Gentianales
order Lamiales clade euasterids II
family Bruniaceae family Columelliaceae [+ family
Desfontainiaceae] family Eremosynaceae
family Escalloniaceae family Paracryphiaceae
family Polyosmaceae family Sphenostemonaceae
family Tribelaceae order Aquifoliales
order Apiales order Dipsacales
order Asterales Note : “ + ....” = optional, as a
segregate of the previous family References
Doyle, J. A. & Hotton, C. L. Diversification of early angiosperm
pollen in a cladistic context. pp. 169–195 in Pollen and Spores. Patterns
of Diversification. Walter S. Judd and Richard G. Olmstead.
"A survey of tricolpate phylogenetic relationships". American Journal of
Botany 91: 1627–1644. doi:10.3732/ajb.91.10.1627. PMID
21652313. Eudicots in Stevens, P. F.. Angiosperm
Phylogeny Website. Version 7, May 2006. External links
Eudicots at the Encyclopedia of Life Eudicots, Tree of Life Web Project
Dicots Plant Life Forms