Properties of Gum Tree Leaves

Eucalyptus is one of several trees called gum.

There are a number of trees that share the name gum and each of these trees is highly distinguishable from the other. Leaves range from large, green and lobed to tiny, silvery blue leaves with no lobes. The name gum is usually in reference to a gummy resin most of them exude. Some of these gums are useful and commercially important to the region in which they grow.

Eucalyptus-Gum Tree

Eucalyptus trees have a large variety of leaf types. They can be narrow and long, or almost completely round. Some leaves are powdery blue, and others are bronzy green. Most eucalyptus have juvenile and mature foliage that looks different. Polyanthemos has round gray-green young foliage and dark green lance-shaped foliage. Eucalyptus pulverulenta has stems that appear to go through the center of the silvery gray leaves, and the mature foliage is long and pointed. The juvenile form is often used in flower arrangements.

Liquidambar-Sweet Gum

The liquidambar has leaves similar to maple leaves, and are often confused for maples. The leaves are palmate, meaning they have five points. They average about 6 to 8 inches across. They have green leaves through the summer. One of their most notable aspects are their highly-colored fall leaves. They put on a show of colors that include yellow, red, purple and orange, usually all at the same time. Most common is the Liquidambar styraciflua, or American sweet gum.

Nyssa-Sour Gum

The leaves of the Nyssa sylvatica are about 2 to 5 inches long and are glossy and dark green. They can be oval or elliptical in shape, and the leaf margins are wavy. The tree is deciduous, and the spring leaves tend to emerge later than most other deciduous trees. When they emerge, their undersides have a soft, rusty-colored tomentum, or fuzz. The fall color starts out as somewhat purplish than ages to a bright scarlet red.

Acacia-Gum Arabic

Both Acacia senegal and Acacia arabica are called gum Arabic. These deciduous trees are native to tropical dry West Africa and India. The leaves are small and grayish-green, have a ferny appearance and appear after the flowers. In fall, the leaves turn yellow, and at the base of the leaves are sharp spines. All parts of the tree exude at least small amounts of a commercially important resin, even the leaves, which is used as a thickener for products like jelly beans.

References

• “Western Garden Book”; Kathleen Norris Brenzel, editor; 2001
• NFT Highlights; Acacia Senegal-Gum Tree With Promise for Agroforestry; Christian Cossalter; 1991
• Purdue University; Acacia Senegal (L.) Willd.; James A. Duke; 1997