AY Honors/Palm Trees/Answer Key

1. Give the general characteristics of the palm tree referring to the following parts:

a. Stem or trunk

A palm trunk are usually a straight, unbranched stem, though rarely the trunk will divide into two branches. Unlike other trees, palms add new growth to the inside of the stem. Other trees add new growth to the outside of the trunk. Thus, on a palm, the living wood is at the heart of the trunk and the old, dead wood is on the outside. In non-palms, the opposite is true.

b. Roots

Palms are monocots, belonging to the same family as grass and bamboo. As such, their roots do not gain much diameter once the plant reaches maturity. Roots of dicots, on the other hand (that is, broadleaf plants such as oaks and maples) continue to grow and get fatter as long as the plant lives. Thus, the roots of a dicot will destroy a sidewalk as it heaves up the concrete, while a palm will do no damage.

Palm roots are usually called "rootballs' because they form round structures. Rootballs will branch a bit but do not grow larger once the tree is mature.

c. Leaves

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.

d. Inflorescence or flowers

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, and radially symmetric. 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.

e. Fruits

The fruit is usually a single-seeded drupe, but some genera (e.g. Salacca) may contain two or more seeds in each fruit.

2. a. What happens when the crown of a palm is cut out?
b. What happens when the trunk of a palm is damaged?

New growth comes from the crown, so if the crown is out out, the tree will die. The outer layers of a palm's trunk consists of dead tissue, and as such, it will not heal (just as your fingernails and hair do not "heal").

3. In the Pacific islands there are several species of palm trees which are helpful to man. Name two of these and list as many ways as you can how each helps man.

Sago Palm

Sago is a starch extracted from the pith inside stems of the sago palm Metroxylon sagu. Sago forms a major staple food for the lowland peoples of New Guinea and the Moluccas where it is called sagu and traditionally is cooked and eaten in the form of a pancake served with fish.

Sago looks like many other starches, and both sago and tapioca are produced commercially in the form of pearls. These two kinds of pearls are similar in appearance and may be used interchangeably in some dishes. This similarity causes some confusion in the names of dishes made with the pearls.

In addition to its use as a food source, the leaves and spathe of the sago palm are used for construction materials, for thatching roofs, and the fibre can be made into rope.

6. Parts of palms are used for food or to help with the preparation of food. From your culture tell how a palm tree or part of it is used as food or in food preparation e.g. sago palm, coconut palm. Tell how to prepare it.

Sago (Metroxylon) is made through the following steps:

1. Felling the sago palm tree;
2. Splitting the trunk open lengthwise;
3. Removing the pith;
4. Crushing and kneading the pith to release the starch;
5. Washing and straining to extract the starch from the fibrous residue;
6. Collection of the raw starch suspension in a settling container.

References

• International Palm Society
• http://www.sunpalmtrees.com/Palm-Tree-Care-Pruning.html