The palm family, Arecaceae, is primarily a tropical family of tree, shrub, and vining monocotyledonous plants, remarkable for the size that many attain without secondary growth (the ability to regenerate vascular tissue in their stems as is present in woody dicots). There are at least twenty-seven hundred species of palms, arranged in about two hundred genera. Palms have the largest leaves of any plant, and their leaves are either fan-shaped (palmate, like a hand) or featherlike (pinnate, with many individual leaflets arranged along a central axis). The stems may be solitary or clustering. In time, many palms form tall woody trunks with the leaves clustered in an aerial crown. Palm flowers are individually small, but are contained in often large flower stems (inflorescences) that appear from within the leafy crown or below the sheathing leaf bases. The majority of palms bear maleand female flowers on the same flower stem, but a number of species may produce separate male or female plants; relatively few palms produce bisexual flowers. A handful of palms grow for many years, flower and fruit once, then die. Most palms are pollinated by insects. Palm fruits range from pea-sized to nearly 18 inches wide. The fruit is either fibrous or fleshy, sometimes berrylike. Palms are important components of tropical rain forests worldwide, but many also occur in seasonally dry tropical ecosystems, including savannas. A few species are mangrovelike, growing in brackish estuaries near the sea. About twelve species are native to the southern United States, the majority in Florida. Coconut, African oil palm, and date palm are the three most important crop species, but many others are significant sources of food, fiber, wax, and construction material in tropical nations.
