- DIVISION: Magnoliophyta
- CLASS: Liliopsida (monocotyledons)
- ORDER: Arecales
- FAMILY: Arecaceae
- GENUS: 59
- SPECIES: 94
Of all trees, perhaps none evokes images of a lush, tropical locale like the palms. As a group, they are indeed basically tropical/subtropical species—but there are always exceptions. Palms inhabit a variety of ecosystems; most live in humid forests, but others have adapted to live in areas subject to regular flooding, and a few species thrive in hot, dry climates. The arid outliers put down roots near springs and have fronds covered with thick cuticles and waxy coatings to avoid losing precious moisture to the dry air.
Palm growth patterns range from shrubs to trees, and include a number of vining species, such as the rattan palms Calamus spp. Depending on the species, a palm tree may have one of two types of leaves: palmate leaves are solid and grow in a bunch at the end of a stem, while feather-like pinnate leaves grow along either side of a stem.
Most palm species have an undivided, single trunk that does not thicken with age. Although solid and rough in texture, the trunk does not contain xylem or bark, but fibers. Bundles of active fibers in the center that feed the new growth at the top of the tree, while clusters of hardened, dead fibers protect the outside.
The root system of a palm is grasslike and fibrous. The roots eagerly seek space, often arising beneath the bark at the base of the trunk. The vigorous network does an amazing job of keeping the tree anchored—palm trees do not have a taproot!
Early on, our ancestors learned that the palm had many uses that would make life easier. From the fruit they could (and we still do) get food, oil, dye, and sugar. The fronds are useful for thatch roofs and cordage, and the trunk provides fuel, building materials, and a sturdy fiber that can be used to make paper or pound into cloth. In addition, the sap provides starch, sugar, and when fermented, wine. Even the wax from the surface of the leaves and trunk has had a variety of uses throughout human history.
Two of the world's most cultivated trees are palms: the coconut palm and the African oil palm. Both are primary sources of vegetable fats. The date palm is known to have been under cultivation for over 5,000 years, and is one of the oldest managed crops.
Our 227 taxa make up the second-largest accredited palm collection in California. Furthermore, we have 32 species that are threatened or endangered in the wild, including highly endangered Carpoxylon macrosperma palms from New Hebrides and Hyophorbe lagenicaulis palms from the Mascarene Islands.
A self-guided tour brochure can be obtained at Guest Services just inside the Zoo entrance, allowing everyone to see some of our exquisite collection.
The San Diego Zoo Safari Park is home to a number of palm species, as well. Gracefully waving their fronds far above the heads of the giraffes, a variety of hardy palm trees can be found in many of the Park's field habitats, providing shade—and sometimes a scratching post—for the inhabitants.
Threatened in the wild because of deforestation, this slow-growing palm is from the coast of South Africa.
RAIN FOREST PALM
This fast grower does best in humid tropical and subtropical areas, but will tolerate cooler temperatures.
Chamaedoreas are understory palms from the rain forests of Mexico and Central and South America. They grow on the forest floor, shaded by both the upper and secondary levels of trees. The common name, bamboo palm, comes from the similarity of their neat, clean trunks to the stalks of the bamboo.
In its native Madagascar, the name for this plant is the satra palm. Local people use it for partitions in walls by emptying the trunks and flattening them into planks. The leaves are used for thatch in roofing and baskets.
Leading you the Safari Park's entrance and onward into Nairobi Village are stately date palms, Old World trees with exotic charm. The date palm has long been considered the tree of life in desert cultures and is associated with fertility and fecundity.
You can see from its leaves why they call this a fishtail palm. Near the end of its 25-year life, the palm grows a number of male and female flower spikes that are 15 to 25 feet (4.5 to 7.6 meters) long and take two years to flower and fruit. Then the palm slowly dies and new plants spring up from the germinating fruit seeds.
Native to rain forests along the central eastern coast of Australia, this palm is also called the bangalow, an Aboriginal word meaning "water-carrying basket." It seems that the tree's crownshaft, out of which the leaves grow, can be cut out and fashioned, with a few clever folds and tucks, into a watertight vessel.
Some gardeners consider this slow-growing native of the Middle East to be the hardiest of all palms.
MEDITERRANEAN FAN PALM
Along with the single-trunk form, some palms have many trunks creating more of a shrub than a tree, such as the Mediterranean fan palm, the most frequently seen example in Southern California.
SHAVING BRUSH PALM
When ripe, the fruits are red. Young plants may have a reddish tinge to the leaves. This plant is also known as the Norfolk palm.
In all palms, the leaves emerge from the top of the trunk, the only growing point. Most emerge in a spiral arrangement; some, like this kind, grow in threes to form a triangular crown.