page_title: Arecaceae
section_title: Morphology
hierarchical_section_title: Arecaceae / Morphology
caption_attribution_description: English: Sawn palm tree trunk. Picture taken in Huerto del Cura, Elche, Spain.
context_page_description: The Arecaceae are a botanical 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 colloquially called palm trees. Currently 181 genera with around 2,600 species are known, most of them 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. However, palms exhibit an enormous diversity in physical characteristics and inhabit nearly every type of habitat within their range, from rainforests to deserts.
  Palms are among the best known and most extensively cultivated plant families. They have been important to humans throughout much of history. Many common products and foods are derived from palms. In contemporary times, palms are also widely used in landscaping, making them one of the most economically important plants. In many historical cultures, because of their importance as food, palms were symbols for such ideas as victory, peace, and fertility.
context_section_description: Whether as shrubs, tree-like, or vines, palms have two methods of growth: solitary or clustered. The common representation is that of a solitary shoot ending in a crown of leaves. This monopodial character may be exhibited by prostrate, trunkless, and trunk-forming members. Some common palms restricted to solitary growth include Washingtonia and Roystonea. Palms may instead grow in sparse though dense clusters. The trunk develops an axillary bud at a leaf node, usually near the base, from which a new shoot emerges. The new shoot, in turn, produces an axillary bud and a clustering habit results. Exclusively sympodial genera include many of the rattans, Guihaia, and Rhapis. Several palm genera have both solitary and clustering members. Palms which are usually solitary may grow in clusters and vice versa. These aberrations suggest the habit operates on a single gene.
  Palms 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 spadix 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 can be either uni- or bisexual. 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 (sometimes berry-like) but some genera (e.g., Salacca) may contain two or more seeds in each fruit.
  Like all monocots, palms do not have the ability to increase the width of a stem (secondary growth) via the same kind of vascular cambium found in non-monocot woody plants. This explains the cylindrical shape of the trunk (almost constant diameter) that is often seen in palms, unlike in ring-forming trees. However, many palms, like some other monocots, do have secondary growth, although because it does not arise from a single vascular cambium producing xylem inwards and phloem outwards, it is often called "anomalous secondary growth".
  The Arecaceae are notable among monocots for their height and for the size of their seeds, leaves, and inflorescences. Ceroxylon quindiuense, Colombia's national tree, is the tallest monocot in the world, reaching up to 60 m tall. The coco de mer (Lodoicea maldivica) has the largest seeds of any plant, 40–50 cm in diameter and weighing 15–30 kg each (coconuts are the second largest). Raffia palms (Raphia spp.) have the largest leaves of any plant, up to 25 m long and 3 m wide. The Corypha species have the largest inflorescence of any plant, up to 7.5 m tall and containing millions of small flowers. Calamus stems can reach 200 m in length.
caption: Sawn palm stem: Palms do not form annual tree rings.
exif: {"Image ImageDescription": "", "Image Make": "Canon", "Image Model": "Canon IXUS 130", "Image Orientation": "Horizontal (normal)", "Image XResolution": "180", "Image YResolution": "180", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2012:09:14 13:17:43", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "240", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "180", "Thumbnail YResolution": "180", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "5108", "Thumbnail JPEGInterchangeFormatLength": "8192", "EXIF ExposureTime": "1/100", "EXIF FNumber": "14/5", "EXIF ISOSpeedRatings": "80", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2012:09:14 13:17:43", "EXIF DateTimeDigitized": "2012:09:14 13:17:43", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "3", "EXIF ShutterSpeedValue": "213/32", "EXIF ApertureValue": "95/32", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "95/32", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "5", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "4320", "EXIF ExifImageLength": "3240", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "Interoperability RelatedImageWidth": "4320", "Interoperability RelatedImageLength": "3240", "EXIF InteroperabilityOffset": "3344", "EXIF FocalPlaneXResolution": "160000/9", "EXIF FocalPlaneYResolution": "1620000/91", "EXIF FocalPlaneResolutionUnit": "2", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Manual", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Landscape"}