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Arecaceae

2007 Schools Wikipedia Selection. Related subjects: Plants

         iArecaceae (palm family)
   Coconut Palm Cocos nucifera
   Coconut Palm Cocos nucifera
         Scientific classification

   Kingdom:  Plantae
   Division: Magnoliophyta
   Class:    Liliopsida
   Order:    Arecales
   Family:   Arecaceae
             Schultz-Schultzenstein

                                   Genera

   Many; see list of Arecaceae genera

   Arecaceae (sometimes known by the names Palmae or Palmaceae, although
   the latter name is taxonomically invalid.), the Palm Family, is a
   family of flowering plants belonging to the monocot order, Arecales.
   There are roughly 202 currently known genera with around 2600 species,
   most of which are restricted to tropical or subtropical climates. Of
   all the families of plants, the Arecaceae is the most easily
   recognizable as distinct by most persons. Most palms are distinguished
   by their large, compound, evergreen leaves arranged at the top of an
   unbranched stem. However, many palms are exceptions to this statement,
   and palms in fact exhibit an enormous diversity in physical
   characteristics. As well as being morphologically diverse, palms also
   inhabit nearly every type of habitat within their range, from
   rainforests to deserts.

   Palms are one of the most well-known and extensively cultivated plant
   families. They have had an important role to humans throughout much of
   history. Many common products and foods are derived from palms, and
   palms are also widely used in landscaping for their exotic appearance,
   making them one of the most economically important plants. In many
   historical cultures, palms were symbols for such ideas as victory,
   peace, and fertility. Today, palms remain a popular symbol for the
   tropics and vacations .

Characteristics and evolution

Range

   The vast majority of palms live in the tropics. Palms are abundant
   throughout the tropical regions around the world, and are present in
   almost every type of habitat in the tropics. Diversity is highest in
   wet, lowland tropical forests, especially in ecological "hotspots" such
   as Madagascar, which has more endemic palms than the entire continental
   Africa. Colombia may have the highest number of palm species in one
   country .

   It is estimated that only 130 palm species grow naturally beyond the
   tropics, most of which grow in the subtropics. The northernmost palm is
   Chamaerops humilis, which reaches 44°N latitude in southern France
   where a mediterranean climate makes weather milder than other places as
   far north. The southernmost palm is the Rhopalostylis sapida, which
   reaches 44°S on the Chatham Islands where an oceanic climate has a
   similar warming effect .

Morphology and habitat

   Washingtonia filifera grove in Palm Canyon, California
   Enlarge
   Washingtonia filifera grove in Palm Canyon, California

   The growth habit of palms is usually a straight, unbranched stem, and
   rarely a dichotomous branching stem or a creeping vine-like habit (
   liana) . They have large evergreen leaves that are either palmately
   ('fan-leaved') or pinnately ('feather-leaved') compound and spirally
   arranged at the top of the stem. The leaves have a tubular sheath at
   the base that usually splits open on one side at maturity . The
   inflorescence is a panicle or spike surrounded by one or more bracts or
   spathes that become woody at maturity. The flowers are generally small
   and white, radially symmetric, and may be bisexual or unisexual. The
   sepals and petals usually number three each and may be distinct or
   joined at the base. The stamens generally number six, with filaments
   that may be separate, attached to each other, or attached to the pistil
   at the base. The fruit is usually a single-seeded drupe , but some
   genera (e.g. Salacca) may contain two or more seeds in each fruit.

   Palms inhabit a variety of habitats. Over two-thirds of palms live in
   tropical forests, where some species grow tall enough to form part of
   the canopy and other shorter palms adapted to shade form part of the
   understory . Some species form pure stands in areas with poor drainage
   or regular flooding, including Raphia hookeri which is common in
   coastal freshwater swamps in West Africa. Other palms live in tropical
   montane habitats above 1000 meters, such as those in the genus
   Ceroxylon native to the Andes. Palms may also live in grasslands and
   scrublands, usually associated with a water source, and in desert oases
   such as the Date Palm. A few palms are adapted to extremely basic lime
   soils, while others are similarly adapted to very acidic serpentine
   soils .

   Arecaceae is notable for having the individual trees with the largest
   seed, largest leaf, largest inflorescence, as well as the tallest
   individual monocot. The Coco de mer (Lodoicea maldivica) has the
   largest seeds of any plant, 40-50 centimeters in diameter and weighing
   15-30 kilograms each. Raffia palms (Raphia spp.), with leaves up to 25
   meters long and 3 meters wide, have the largest leaves of any plant.
   The Corypha species have the largest inflorescence of any plant, up to
   7.5 meters tall and containing millions of small flowers. Ceroxylon
   quindiuense, Colombia's national tree, is the tallest monocot in the
   world, reaching heights of 70 meters .

Taxonomy

   A coconut palm.
   Enlarge
   A coconut palm.

   Palms are a monophyletic group of plants, meaning that the group
   consists of a common ancestor and all its descendants . Extensive
   taxonomic research on palms began with botanist H.E. Moore, who
   organized palms into fifteen 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 six subfamilies . A few
   general traits of each subfamily are listed.

   Coryphoideae is the most diverse subfamily and is a paraphyletic group,
   meaning that all members of the group share a common ancestor but the
   group does not include all the ancestor's descendants. Most palms in
   this subfamily have palmately lobed leaves and solitary flowers with
   three, sometimes four carpels. The fruit normally develops from only
   one carpel. Subfamily Calamoideae includes the climbing palms such as
   rattans. The leaves are usually pinnate; derived characters (
   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 Nypoideae contains only one genus and one species, Nypa
   fruticans, which has large pinnate leaves. The fruit is unusual in that
   it floats, and the stem is dichotomously branched, also unusual in
   palms. Subfamily Ceroxyloideae has small to medium-sized flowers that
   spirally arranged, with a gynoecium of three joined carpels. Arecoideae
   is the largest subfamily with six diverse tribes 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. Phytelephantoideae is a monoecious subfamily.
   Members of this group have distinct monopodial flower clusters. Other
   distinct features include a gynoecium with five to ten joined carpels,
   and flowers with more than three parts per whorl. Fruits are
   multiseeded and have multiple parts .

   Currently, few extensive phylogenetic studies of 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 that Calamoideae is monophyletic, and that
   Ceroxyloideae and Coryphoideae are paraphyletic. The relationships of
   Arecoideae are uncertain but it is possibly related to Ceroxyloideae
   and Phytelephantoideae. 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 .

Selected genera

   The orange fruit on a palm tree.
   Enlarge
   The orange fruit on a palm tree.
     * Areca – Betel palm
     * Bactris – Pupunha
     * Borassus – Palmyra palm
     * Calamus – Rattan palm
     * Cocos – Coconut
     * Copernicia – Carnauba wax palm
     * Elaeis – Oil palm
     * Euterpe – Cabbage Heart palm, Açaí palm
     * Jubaea – Chilean Wine palm, Coquito palm
     * Metroxylon – Sago palm
     * Phoenix – Date palm
     * Raphia – Raffia palm
     * Roystonea – Royal palm
     * Sabal – Palmettos
     * Salacca – Salak
     * Trachycarpus – Windmill palm, Kumaon palm
     * Washingtonia

   See list of Arecaceae genera for a complete listing of genera.

Evolution

   Arecaceae is the first modern family of monocots that is clearly
   represented in the fossil record. Palms first appear in the fossil
   record around 80 million years ago, during the late Cretaceous Period.
   The first modern species, such as Nypa fruticans and Acromia aculeata,
   appeared 69-70 million years ago, confirmed by fossil Nypa pollen dated
   to 70 million years ago. Palms appear to have undergone an early period
   of adaptive radiation. By 60 million years ago, many of the modern,
   specialized genera of palms appeared and became widespread and common,
   much more widespread than their range today. Because palms separated
   from the monocots earlier than other families, they developed more
   intrafamilial specialization and diversity. By tracing back these
   diverse characteristics of palms to the basic structures of monocots,
   palms may be valuable in studying monocot evolution .

Conservation

   Pritchardia affinis, a critically endangered species endemic to the
   Hawaiian Islands.
   Enlarge
   Pritchardia affinis, a critically endangered species endemic to the
   Hawaiian Islands.

   Unfortunately, like many other plants, palms have been threatened by
   human intervention and exploitation. The greatest risk to palms is
   destruction of habitat, especially in the tropical forests, due to
   urbanization, wood-chipping, mining, and conversion to farmland. Palms
   rarely reproduce after such great changes in the habitat, and palms
   with a small habitat range are most vulnerable to them. The harvesting
   of heart of palm, a delicacy in salads, also poses a threat because it
   is derived from the inner core of the tree and thus harvesting kills
   the tree. The use of rattan palms in furniture has caused a major
   population decrease in these species that has negatively affected local
   and international markets as well as biodiversity in the area . The
   sale of seeds to nurseries and collectors is another threat, and the
   seeds of popular palms are sometimes harvested directly from the wild.
   At least 100 palm species are currently endangered, and nine species
   have reportedly recently become extinct .

   However, several factors make palm conservation more difficult. Palms
   live in almost every type of habitat and have tremendous morphological
   diversity. Most palm seeds lose viability quickly, but they cannot be
   preserved in low temperatures because the cold kills the embryo. Using
   botanical gardens for conservation also presents problems, since they
   can only house a few plants of any species and cannot truly imitate the
   natural setting .

   The Palm Specialist Group of the World Conservation Union (IUCN) began
   in 1984 and has performed a series of three studies in order to find
   basic information on the status of palms in the wild, utilization of
   wild palms, and palms under cultivation. Two projects on palm
   conservation and utilization supported by the World Wildlife Fund took
   place from 1985-1990 and 1986-1991, in the American tropics and
   southeast Asia respectively. Both studies produced a large amount of
   new data and publications on palms. Preparation of a global action plan
   for palm conservation began in 1991, supported by the IUCN, and was
   published in 1996 .

Uses and cultivation

   Fruit of the Date Palm Phoenix dactylifera
   Enlarge
   Fruit of the Date Palm Phoenix dactylifera

   Human use of palms is as old or older than human civilization itself,
   starting with the cultivation of the Date Palm by Mesopotamians and
   other Middle Eastern peoples 5000 years or more ago. Date wood, pits
   for storing dates, and other remains of the Date Palm have been found
   in Mesopotamian sites.The Date Palm had a tremendous effect on the
   history of the Middle East. W.H. Barreveld wrote:

          "One could go as far as to say that, had the date palm not
          existed, the expansion of the human race into the hot and barren
          parts of the "old" world would have been much more restricted.
          The date palm not only provided a concentrated energy food,
          which could be easily stored and carried along on long journeys
          across the deserts, it also created a more amenable habitat for
          the people to live in by providing shade and protection from the
          desert winds (Fig. 1). In addition, the date palm also yielded a
          variety of products for use in agricultural production and for
          domestic utensils, and practically all parts of the palm had a
          useful purpose."

   An indication of the importance of Palms is that they are mentioned
   more than 30 times in the Bible, and at least 22 times in the Koran.

   The type member of Arecaceae is the Areca palm, the fruit of which, the
   betel nut, is chewed with the betel leaf for intoxicating effects. Also
   belonging to the family are the Date Palm, harvested for its edible
   fruit; Rattans, whose stems are used extensively in furniture and
   baskets; and the Coconut. Palm oil is an edible vegetable oil produced
   by the oil palms in the genus Elaeis. Several species are harvested for
   heart of palm, a vegetable eaten in salads. Palm sap is sometimes
   fermented to produce palm wine or toddy, an alcoholic beverage common
   in parts of Africa, India, and the Philippines . The Palm Sunday
   festival uses palm leaves, usually from the Date Palm, hence the name.
   Dragon's blood, a red resin used traditionally in medicine, varnish,
   and dyes, may be obtained from the fruit of Daemonorops species. Coir
   is a coarse water-resistant fibre extracted from the outer shell of
   coconuts, used in doormats, brushes, mattresses, and ropes. Some
   indigenous groups living in palm-rich areas use palms to make many of
   their necessary items and food. Sago, for example, a starch made from
   the pith of the trunk of the Sago Palm Metroxylon sagu, is a major
   staple food for lowland peoples of New Guinea and the Moluccas. Palm
   leaves are also valuable to some peoples as a material for thatching or
   clothing .
   Washingtonia robusta trees line Ocean Avenue in Santa Monica,
   California.
   Enlarge
   Washingtonia robusta trees line Ocean Avenue in Santa Monica,
   California.

   Today, palms are valuable as ornamental plants and are often grown
   along streets in tropical and subtropical cities, and also along the
   Mediterranean coast in Europe. Farther north, palms are a common
   feature in botanical gardens or as indoor plants. Few palms tolerate
   severe cold, however, and the majority of the species are tropical or
   subtropical. The three most cold-tolerant species are Trachycarpus
   fortunei, native to eastern Asia, and Rhapidophyllum hystrix and Sabal
   minor, both native to the southeastern United States . For more
   details, see hardy palms.

   The southeastern state of South Carolina is nicknamed the Palmetto
   State after the Cabbage Palmetto, logs from which were used to build
   the fort at Fort Moultrie. During the American Revolutionary War they
   were invaluable to those defending the fort, because their spongy wood
   absorbed or deflected the British cannonballs. Some palms can be grown
   as far north as Maryland, Arkansas, and even up along the Pacific coast
   to Oregon, Washington and British Columbia, where ocean winds have a
   warming effect. There have even been known species of transplanted
   palms that have survived as far north as southern New Jersey. The
   Chinese Trachycarpus fortunei is being grown experimentally on the
   Faroe Islands at 62°N, with young plants doing well so far .

Symbolism

   Waving palm leaves to welcome Christ into Jerusalem
   Enlarge
   Waving palm leaves to welcome Christ into Jerusalem

   The palm branch was a symbol of triumph and victory in pre-Christian
   times. The Romans rewarded champions of the games and celebrated
   military successes with palm branches. The motto of the HMS Nelson and
   the University of Southern California is "Palmam qui meruit ferat",
   which means in Latin, "Let him bear the palm who has deserved it". Jews
   followed a similar tradition of carrying palm branches during festive
   times.

   Early Christians used the palm branch to symbolize the victory of the
   faithful over enemies of the soul, as in the Palm Sunday festival
   celebrating the triumphal entry of Jesus into Jerusalem. In Christian
   art, martyrs were usually shown holding palms representing the victory
   of spirit over flesh, and it was widely believed that a picture of a
   palm on a tomb meant that a martyr was buried there. Origen calls the
   palm (In Joan., XXXI) the symbol of victory in that war waged by the
   spirit against the flesh. In this sense it was especially applicable to
   martyrs, the victors par excellence over the spiritual foes of mankind;
   hence the frequent occurrence in the Acts of the martyrs of such
   expressions as "he received the palm of martyrdom." On 10 April 1688 it
   was decided by the Congregation of Rites that the palm when found
   depicted on catacomb tombs was to be regarded as a proof that a martyr
   had been interred there. Subsequently this opinion was acknowledged by
   Mabillon, Muratori, Benedict XIV and others to be untenable; further
   investigation showed that the palm was represented not only on tombs of
   the post-persecution era, but even on pagan tombs. The general
   significance of the palm on early Christian monuments is slightly
   modified according to its association with other symbols (e.g., with
   the monogram of Christ, the Ichthus (Fish), or the Good Shepherd). On
   some later monuments the palm was represented merely as an ornament
   separating two scenes Palms also represented heaven, evidenced by
   ancient art often depicting Jesus in heaven among palms.

   In Judaism, the palm represents peace and plenty, and is one of the
   Four Species of Sukkot; the palm may also symbolize the Tree of Life in
   Kabbalah. The sacred tree in Assyrian mythology is a palm that
   symbolizes Ishtar connecting heaven, the crown of the tree, and earth,
   the base of the trunk. Muhammad is said to have built his home out of
   palm, and the palm symbolizes rest and hospitality in many cultures of
   the Middle East. Palm stems represented long life to the Ancient
   Egyptians, and the god Huh was often shown holding a palm stem in one
   or both hands. The palm tree was a sacred sign of Apollo in Ancient
   Greece because he had been born under one in Delos . In ancient
   Mesopotamia, the Date Palm may have represented fertility in humans.
   The Mesopotamian goddess Inanna, who had a part in the sacred marriage
   ritual, considered herself the one who made the dates abundant .

   Today, the palm, especially the Coconut, remains a symbol of the
   stereotypical tropical island paradise .

   Palms appear on the flags and seals of several places where they are
   native, including those of Haiti, Guam, Florida and South Carolina.

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