Eucalyptus Tree Adaptations

Koala bears are tolerant of the oil in the Eucalyptus tree.

The Eucalyptus is a genus of plants mostly endemic to Australia. Because of its unique circumstances, it also has a number of adaptations that make it specifically attuned to its environment so that it can continue to survive in Australia.

Adaptations

Adaptations are features or structures that contribute to an organism's fitness--in other words, its survival rate. Not every feature is an adaptation, and one must separate incidental features from what are immediately beneficial to survival, which, even if it seems immediately obvious, still must be proven to be advantageous enough to impart the organism a greater fitness level.

Gum

Eucalyptus trees are also sometimes known as gum trees because of the amount of sticky, gum-like sap that they have in their trunks. This gum or sap is the product of vascular tissue that transports substances such as water, sugars, hormones, and minerals all throughout the plant.

Oil

Its leaves contain glands that produce volatile oil, which acts as a powerful toxic disinfectant. The oil is volatile because it evaporates when exposed to the air at normal temperatures. Despite this defense, some marsupials like koalas and possums are tolerant of the oils, and there are a number of insect pests that still use the eucalyptus as a food source.

Flower Cap

Both the petals and stamen are fused into a cap called the operculum, from which the eucalyptus derives its name ("calyptos" means "well" and "covered"). This operculum protects and conceals the flower at the bud stage and then is shed once the flower begins to open.

Seed Pods

After flowering, eucalyptus seeds develop a hard, woody, protective "pod", which are unique, so they are often used to identify entire species. Inside they contain a number of true seeds and infertile chaff. Eucalyptus plants also have an excellent ability to regenerate from seeds or shoots, increasing their ability to recover from brushfires.

References

• Australian Native Plant Society: Eucalyptus, Corymbia and Angophora