Urticales is an
order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
of
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...
s. Before
molecular phylogenetics
Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
became an important part of
plant taxonomy
Plant taxonomy is the science that finds, identifies, describes, classifies, and names plants. It is one of the main branches of taxonomy (the science that finds, describes, classifies, and names living things).
Plant taxonomy is closely alli ...
, Urticales was recognized in many, perhaps even most,
systems
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and expresse ...
of
plant classification, with some variations in
circumscription. Among these is the
Cronquist system
The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in a series of monographs and texts, including ''The Evolution and Classification of Flowering Plants'' (1968; 2nd edition, 1988) ...
(1981), which placed the order in the
subclass Hamamelidae
Hamamelididae is an obsolete botanical name at the rank of subclass.
Because some hamamelidid members bear aments (''i.e.'', catkins), this subclass has been formerly known as ''Amentiferae''. Based on molecular phylogeny works, Hamamelididae a ...
, as comprising:
*
Barbeyaceae
''Barbeya'' is the only genus in the family Barbeyaceae, and has only one species, ''Barbeya oleoides''. It is a small tree native to the mountains of Somalia, Ethiopia, and the Arabian Peninsula. It can be found locally abundant in the transitio ...
*
Cannabaceae
*
Cecropiaceae
*
Moraceae
*
Ulmaceae
*
Urticaceae
The Urticaceae are a family, the nettle family, of flowering plants. The family name comes from the genus ''Urtica''. The Urticaceae include a number of well-known and useful plants, including nettles in the genus ''Urtica'', ramie (''Boehmeri ...
In the
APG III system
The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy being developed by the Angiosperm Phylogeny Group (APG). Published in 2009, it was superseded in 2016 by a fu ...
(2009), the plants belonging to this order, along with four other families, constitute the order
Rosales. Cecropiaceae is no longer recognized as separate from Urticaceae. The families Ulmaceae, Cannabaceae, Moraceae, and Urticaceae form a
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 ter ...
that has strong
statistical support in
phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups ...
analyses of
DNA sequence
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. T ...
s.
[Shu-dong Zhang, Douglas E. Soltis, Yang Yang, De-zhu Li, and Ting-shuang Yi. "Multi-gene analysis provides a well-supported phylogeny of Rosales". ''Molecular Phylogenetics and Evolution'' 60(1):21-28.] This clade has been informally called the urticalean rosids.
[Kenneth J. Sytsma, Jeffery Morawetz, J. Chris Pires, Molly Nepokroeff, Elena Conti, Michelle Zjhra, Jocelyn C. Hall, and Mark W. Chase. (2002). Urticalean rosids: Circumscription, rosid ancestry, and phylogenetics based on ''rbcL'', ''trnL-F'', and ''ndhF'' sequences. '' American Journal of Botany'' 89(9): 1531-1546]
PDF fulltext
/ref>
Urticalean rosids refers to the relationships amongst several families of angiosperms, and now includes more than 2,500 species.
The families are:
* Cannabaceae
* Moraceae
* Ulmaceae
* Urticaceae
The Urticaceae are a family, the nettle family, of flowering plants. The family name comes from the genus ''Urtica''. The Urticaceae include a number of well-known and useful plants, including nettles in the genus ''Urtica'', ramie (''Boehmeri ...
[Qiu Y.-L. M. W. Chase S. B. Hoot E. Conti P. R. Crane K. J. Sytsma C. R. Parks 1998. Phylogenetics of the Hamamelidae and their allies: parsimony analyses of nucleotide sequences of the plastid gene rbcL. International Journal of Plant Sciences 159: 891-905.]
The relationships within the "urticalean lineage" are now considered to be within the Rosales.[APG (Angiosperm Phylogeny Group). 1998. An ordinal classification for the families of flowering plants. Annals of the Missouri Botanical Garden 85: 531-553.] The Moraceae and Urticaceae account for approximately 90% of the diversity within the clade.[Sytsma, Kenneth J., Jeffery Morawetz, J. Chris Pires, Molly Nepokroeff, Elena Conti, Michelle Zjra, Jocelyn C. Hall, and Mark W. Chase. 2001. Urticalean Rosids: Circumscription, Rosid Ancestry, and Phylogenetics Based on RbcL, TrnL-F, and NdhF Sequences. American Journal of Botany]
Analysis of DNA samples in ''rbcL'', ''trnL-F'', and ''ndhF'' plastid regions suggests that Urticalean rosids are derived out of a lineage including Barbeyaceae
''Barbeya'' is the only genus in the family Barbeyaceae, and has only one species, ''Barbeya oleoides''. It is a small tree native to the mountains of Somalia, Ethiopia, and the Arabian Peninsula. It can be found locally abundant in the transitio ...
, Dirachmaceae, Elaeagnaceae
The Elaeagnaceae are a plant family, the oleaster family, of the order Rosales comprising small trees and shrubs, native to temperate regions of the Northern Hemisphere, south into tropical Asia and Australia. The family has about 60 species ...
, and Rhamnaceae
The Rhamnaceae are a large family of flowering plants, mostly trees, shrubs, and some vines, commonly called the buckthorn family. Rhamnaceae is included in the order Rosales.
The family contains about 55 genera and 950 species. The Rhamnaceae ...
, with Rosaceae less closely related.[Tobe H. and T. Takaso 1996. Trichome micromorphology in Celtidaceae and Ulmaceae (Urticales). Acta Phytotaxonomica et Geobotanica 47: 153–168.]
* A reduced stamen count to one whorl or less[Judd W. S. C. S. Campbell E. A. Kellogg P. F. Stevens 1999. Plant systematics: a phylogenetic approach. Sinauer Associates, Sunderland, Massachusetts, USA.][Stevens P. F. 2001. Angiosperm phylogeny website, v. 2, August 2001. http://www.mobot.org/MOBOT/research/APweb/.]
* Presence of inconspicuous flowers with up to five stamens
References
{{Reflist
Historically recognized angiosperm orders