Editing Arecaceae (section)

==Taxonomy==

[[File:Roystonea-2.jpg|thumb|right|Two ''[[Roystonea regia]]'' specimens. The characteristic crownshaft and apex shoot, or 'spear', are visible.]]

Palms are a [[monophyly|monophyletic]] group of plants, meaning the group consists of a common ancestor and all its descendants.<ref name="VPEintro" /> Extensive taxonomic research on palms began with botanist [[Harold E. Moore|H.E. Moore]], who organized palms into 15 major groups based mostly on general morphological characteristics. The following classification, proposed by N.W. Uhl and J. Dransfield in 1987, is a revision of Moore's classification that organizes palms into 6 subfamilies.<ref>N. W. Uhl, J. Dransfield (1987). ''Genera palmarum: a classification of palms based on the work of Harold E. Moore, Jr.'' (Allen Press, Lawrence, Kansas).</ref> A few general traits of each subfamily are listed below.
* Subfamily '''{{vanchor|Arecoideae|text=[[Arecoideae]]}}''' are the largest subfamily with [[List of Arecaceae genera#Subfamily Arecoideae|14 tribes]] and containing over 100 genera. All tribes have pinnate or bipinnate leaves and flowers arranged in groups of three, with a central pistillate and two staminate flowers.
* Subfamily '''{{vanchor|Calamoideae|text=[[Calamoideae]]}}''' includes the climbing palms, such as rattans. The leaves are usually pinnate; derived characters ([[synapomorphy|synapomorphies]]) include spines on various organs, organs specialized for climbing, an extension of the main stem of the leaf-bearing reflexed spines, and overlapping scales covering the fruit and ovary.
* Subfamily '''{{vanchor|Ceroxyloideae|text=[[Ceroxyloideae]]}}''' has small to medium-sized flowers, spirally arranged, with a [[gynoecium]] of three joined carpels.
* Subfamily '''{{vanchor|Coryphoideae|text=[[Coryphoideae]]}}''' are the second-largest subfamily with [[List of Arecaceae genera#Subfamily Coryphoideae|8 tribes]]. Most palms in this subfamily have palmately lobed leaves and solitary flowers with three, or sometimes four [[carpel]]s. The fruit normally develops from only one carpel.
* Subfamily '''{{vanchor|Nypoideae|text=[[Nypoideae]]}}''' contains only one species, ''[[Nypa fruticans]]'',<ref>{{Cite book |last=John Leslie Dowe |url=https://books.google.com/books?id=Fk5ud3uuLW8C&q=Nypoideae&pg=PA83 |title=Australian Palms: Biogeography, Ecology and Systematics |publisher=Csiro |year=2010 |isbn=9780643096158 |page=83 |access-date=April 20, 2012 |archive-url=https://web.archive.org/web/20140202163500/http://books.google.com.vn/books?id=Fk5ud3uuLW8C&pg=PA83&lpg=PA83&dq=Nypoideae&source=bl&ots=GLh89V2U04&sig=-rXN3kSbWv1-bOs8xgcDThEfC84&hl=vi&sa=X&ei=ekWRT4iCJ4TeigfavvSJBA&ved=0CDIQ6AEwAg#v=onepage&q=Nypoideae&f=false |archive-date=February 2, 2014 |url-status=live}}</ref> which has large, pinnate leaves. The fruit is unusual in that it floats, and the stem is underground and dichotomously branched, also unusual in palms.

The '''{{vanchor|Phytelephantoideae|text=[[Phytelepheae|Phytelephantoideae]]}}''' is the sixth subfamily of Arecaceae in N.W. Uhl and J. Dransfield's 1987 classification. Members of this group have distinct monopodial flower clusters. Other distinct features include a gynoecium with five to 10 joined carpels, and flowers with more than three parts per whorl. Fruits are multiple-seeded and have multiple parts. From the modern phylogenomic data, the Phytelephantoideae are tribe in the  [[Ceroxyloideae#Phytelepheae|Ceroxyloideae]] subfamily.<ref name="UA" />

Currently, few extensive phylogenetic studies of the Arecaceae exist. In 1997, Baker ''et al.'' explored subfamily and tribe relationships using chloroplast [[DNA]] from 60 genera from all subfamilies and tribes. The results strongly showed the Calamoideae are monophyletic, and Ceroxyloideae and Coryphoideae are paraphyletic. The relationships of Arecoideae are uncertain, but they are possibly related to the Ceroxyloideae and Phytelephantoideae. Studies have suggested the lack of a fully resolved hypothesis for the relationships within the family is due to a variety of factors, including difficulties in selecting appropriate outgroups, [[homoplasy]] in morphological character states, slow rates of molecular evolution important for the use of standard [[DNA marker]]s, and character polarization.<ref>{{Cite journal |last=Hahn |first=William J. |year=2002 |title=A Molecular Phylogenetic Study of the Palmae (Arecaceae) Based on ''atp''B, ''rbc''L, and 18S nrDNA Sequences |journal=Systematic Biology |volume=51 |issue=1 |pages=92–112 |doi=10.1080/106351502753475899 |jstor=3070898 |pmid=11943094 |doi-access=free}}</ref> However, hybridization has been observed among ''Orbignya'' and ''Phoenix'' species, and using chloroplast DNA in cladistic studies may produce inaccurate results due to maternal inheritance of the chloroplast DNA. Chemical and molecular data from non-organelle DNA, for example, could be more effective for studying palm phylogeny.<ref name="UA">{{Cite web |title=Palms on the University of Arizona Campus |url=http://arboretum.arizona.edu/palms.htm |url-status=dead |archive-url=https://web.archive.org/web/20060621003136/http://arboretum.arizona.edu/palms.htm |archive-date=June 21, 2006}}</ref>

Recently, nuclear genomes and transcriptomes have been used to reconstruct the phylogeny of palms. This has revealed, for example, that a whole-genome duplication event occurred early in the evolution of the Arecaceae lineage, that was not experienced by its sister clade, the [[Dasypogonaceae]].<ref>{{Cite journal |last1=Barrett |first1=C. F. |last2=McKain |first2=M. R. |last3=Sinn |first3=B. T. |last4=Ge |first4=X. J. |last5=Zhang |first5=Y. |last6=Antonelli |first6=A. |last7=Bacon |first7=C. D. |date=2019 |title=Ancient Polyploidy and Genome Evolution in Palms |url=https://academic.oup.com/gbe/article/11/5/1501/5481000 |journal=Genome Biology and Evolution |volume=11 |issue=5 |pages=1501–1511 |doi=10.1093/gbe/evz092 |pmc=6535811 |pmid=31028709 |access-date=2023-11-07}}</ref>

For a [[phylogenetic tree]] of the family, see the [[List of Arecaceae genera#Taxonomy|list of Arecaceae genera]].