AY Honors/Wattles/Answer Key
1. What is the approximate number of named varieties of wattles in Australia?
There are roughly 1300 species of Wattles worldwide, about 960 of them native to Australia, with the remainder spread around the tropical to warm-temperate regions of both hemispheres, including Africa, southern Asia, and the Americas. Wattles are trees and shrubs belonging to the genus Acacia.
2. a. What are phyllodes?
b. What work do they do for the plant?
c. Why are phyllodes so important in the study of acacias?
Phyllodes are modified leaf stems (also called petioles). In some plants, the petioles become flattened and widened, and the true leaves may become reduced or vanish altogether. Thus, the phyllode comes to serve the purpose of the leaf. Phyllodes are common in the genus Acacia, especially the Australian species, at one time put in Acacia subgenus Phyllodineae. Sometimes, especially on younger plants, partially formed phyllodes bearing reduced leaves can be seen.
In Acacia koa, the phyllodes are leathery and thick, allowing the tree to survive stressful environments. The petiole allows partially submerged aquatic plants to have leaves floating at different depths; the petiole being between the node and the stem.
The vertical orientation of the phyllodes protects them from intense sunlight, as with their edges towards the sky and earth they do not intercept light so fully as horizontally placed leaves.
Phyllodes are important in the study of Acacias because they are distinctive and can therefore be used to determine which species an Acacia belongs to.
- Phyllode details are important as they are used as "key" characters in identification. Some important things to note are size and shape of the phyllodes, the type and number of veins, whether penni- or net-veins, length of leaf stalk and gland position. - Marion Simmons, Association of Societies for Growing Australian Plants (ASGAP)
3. How are acacias classified into two major groups?
4. How does the shape of the seed pod and the way the seeds lie in the pod help in identification?
5. How many acacias in your state have true leaves (bipinnate) when adults?
6 a. In seeding acacias what is seen first, true leaves or phyllodes?
6 b. How many have true leaves?
7. What must happen to an acacia seed before it will germinate and grow?
8. What acacias phyllodes are used to feed stock in times of drought?
9. What is the bark of some acacias used for in Australia?
10. What species of acacias are used for furniture making?
Most acacia species are used for valuable timber; such are Acacia melanoxylon (Blackwood) from Australia, which attains a great size; its wood is used for furniture, and takes a high polish; and Acacia omalophylla (Myall Wood, also Australian), which yields a fragrant timber, used for ornamental purposes.
