Arecaceae
The Arecaceae (/ærəˈkeɪsiaɪ/) is a family of perennial, flowering plants in the monocot order Arecales. Their growth form can be climbers, shrubs, tree-like and stemless plants, all commonly known as palms. Those having a tree-like form are called palm trees.[3] Currently, 181 genera with around 2,600 species are known,[4][5] most of which are restricted to tropical and subtropical climates. Most palms are distinguished by their large, compound, evergreen leaves, known as fronds, arranged at the top of an unbranched stem, except for the Hyphaene genus, who has branched palms. However, palms exhibit an enormous diversity in physical characteristics and inhabit nearly every type of habitat within their range, from rainforests to deserts.
Not to be confused with the heather family Ericaceae, the arum family Araceae or the ivy family Araliaceae.Palms are among the best known and most extensively cultivated plant families. They have been important to humans throughout much of history, especially in regions like the Middle East and North Africa. A wide range of common products and foods are derived from palms. In contemporary times, palms are also widely used in landscaping. In many historical cultures, because of their importance as food, palms were symbols for such ideas as victory, peace, and fertility.
Etymology[edit]
The word Arecaceae is derived from the word areca with the suffix "-aceae". Areca is derived from Portuguese, via Malayalam അടയ്ക്ക (aṭaykka), which is from Dravidian *aṭ-ay-kkāy ("areca nut"). The suffix -aceae is the feminine plural of the Latin -āceus ("resembling").
Palm originates from Latin palma semantically overlapping with sense of "hand front" (due to similar splayed shape) ultimately from Proto-Indo-European *pl̥h₂meh₂, a direct descendant folm once existed in Old English.[6]
Palms are a monophyletic group of plants, meaning the group consists of a common ancestor and all its descendants.[16] Extensive taxonomic research on palms began with botanist 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.[17] A few general traits of each subfamily are listed below.
The 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 subfamily.[19]
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 markers, and character polarization.[20] 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.[19]
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.[21]
For a phylogenetic tree of the family, see the list of Arecaceae genera.
Human use of palms is at least as old as human civilization itself, starting with the cultivation of the date palm by Mesopotamians and other Middle Eastern peoples 5,000 years or more ago.[24] Date wood, pits for storing dates, and other remains of the date palm have been found in Mesopotamian sites.[25][26] The date palm had a significant effect on the history of the Middle East and North Africa.[27] In the text “Date Palm Products” (1993), W.H. Barreveld wrote:[28]
An indication of the importance of palms in ancient times is that they are mentioned more than 30 times in the Bible,[29] and at least 22 times in the Quran.[30] The Torah also references the “70 date palm trees,” which symbolize the 70 aspects of Torah that are revealed to those who “eat of its fruit.”[31]
Arecaceae have great economic importance, including coconut products, oils, dates, palm syrup, ivory nuts, carnauba wax, rattan cane, raffia, and palm wood. This family supplies a large amount of the human diet and several other human uses, both by absolute amount produced and by number of species domesticated.[32] This is far higher than almost any other plant family, sixth out of domesticated crops in the human diet, and first in total economic value produced – sharing the top spot with the Poaceae and Fabaceae.[32] These human uses have also spread many Arecaceae species around the world.[32]
Along with dates mentioned above, members of the palm family with human uses are numerous:
Some pests are specialists to particular taxa. Pests that attack a variety of species of palms include:
Some species commonly called palms, though they are not true palms, include: