AY Honors/Eucalypts/Answer Key
1. How many different species of Eucalypts have been named in Australia?
There are three genera of eucalypts identified by scientists:
- Eucalyptus which includes more than seven hundred species,
- Corymbia which includes 113 species, and
- Angophora which includes 10 species.
So the total number of eucalypts is greater than 723.
2a. Where does the name Eucalypt come from?
2b. To what family do Eucalypts belong?
The name eucalypt comes from the Greek, ευκάλυπτος meaning "Well covered."
The eucalypts belong to the Myrtaceae or Myrtle family. Other members of the myrtle family include myrtle, clove, guava, feijoa, and allspice.
3a. In what other parts of the world do Eucalypts grow?
3b. In how many are they indigenous to that country?
Eucalyptus are mostly native to Australia, with a very small number native to three other countries; New Guinea, Indonesia, and the Philippines islands.
Many Eucalyptus have been planted in various parts of the world including the dry regions of Southern California and in Africa, Spain, South America, and on forestry plantations in India and China.
4a. Which country has the tallest Hardwood?
4b. Where is it growing?
4c. How tall is it?
4d. Which country has the tallest flowering trees?
Eucalyptus regnans, known variously by the common names Mountain Ash, Victorian Ash, Swamp Gum, Tasmanian Oak or Stringy Gum, is a species of Eucalyptus native to southeastern Australia, in Tasmania and Victoria. It is known to attain heights over 295 feet (90 metres) and is described as the tallest of the flowering plants.
5. Into what groups are Eucalypts divided and what feature is used for this purpose?
6. How do Eucalypts adapt to
a. Frequent bush fires?
On warm days vaporized eucalyptus oil rises above the bush to create the characteristic distant blue haze of the Australian landscape. Eucalyptus oil is highly flammable (trees have been known to explode) and bush fires can travel easily through the oil-rich air of the tree crowns. The dead bark and fallen branches are also flammable. Eucalypts are well adapted for periodic fires, in fact most species are dependent on them for spread and regeneration. They do this via lignotubers, epicormic buds under the bark and from fire-germinated seeds sprouting in the ashes.
A lignotuber is a starchy swelling on underground stems or roots. Jarrah and mallee plants use them as a life support system in case of fire or animal damage. They are able to sprout back from buds on the surface of the lignotuber. This is known as coppicing.
Eucalypts regenerate quickly after fire. After the Canberra bushfires of 2003, hectares of imported species were killed, but in a matter of weeks the gum trees were putting out suckers and looking generally healthy.
b. Arid regions?
7a. From what species do they extract Eucalyptus oil?
7b. Where is it done in Australia?
The Blue mallee, or Blue-leaved mallee (Eucalyptus polybractea) is a small multi-trunked sclerophyll tree that grows naturally in western New South Wales and Victoria, Australia. E. polybractea is the major species used to produce high grade cineole-rich (up to 91% 1,8-cineole) Eucalyptus oil, yielding 0.7-5% fresh weight. The oil is primarily used medicinally and for flavoring.
Eucalyptol (another name for the oil), is produced in Victoria, Australia in the regions of St. Arnaud, Inglewood, and Wedderburn.
