According to Reference.com, palmettos are dwarf palm trees that have fan-like leaves and are common in the Southeastern United States. Most palm trees that are considered palmettos fall into the genus Sabal, and the name "palmetto" means "little palm" in Spanish. Palms in the genera Serenoa and Thrinax are also sometimes considered palmettos.
Mother Nature Network states that there are over 2,500 species of palm trees worldwide. These fall into the family Arecaceae, and they are found in warm climates ranging from the desert to the rain forest. Not all palms are definitive trees; some grow as shrubs and vine-like plants. A characteristic of all palm trees is that they have two kinds of leaves. The pinate leaves are like feathers, and they grow out of the side of the trunk or stem. The palmate leaves are longer and larger, and they grow out of the end of the trunk in a large bunch.
Although several types of palm trees are referred to as palmettos, a common one is the Sabal Palmetto, a genus of several related palm tree species found throughout South Carolina. According to About.com, this type is typically 40 to 50 feet in height at maturity. It has a sturdy trunk, and its leaves have long, parallel veins.