To the average observer, all eucalyptus species tend to look the same. However, if its distinct qualities are observed deeply, it can be quite simple to identify. Let us look at these distinct physical characteristics to differentiate between its different species.
Learn How to Identify Eucalyptus
Eucalyptus is native to Australia. It belongs to the Myrtaceae family. There are numerous varieties of eucalyptus having a similar nomenclature. Trees within a eucalyptus grove grow near each other. By closely observing the physical characteristics of eucalyptus or gum trees, we can differentiate it from other tree species.
When identifying a eucalypt, you will come across a striking arrangement of leaf types in the form of:
• completely isolated and connate pairs of leaves
• closely packed and spirally arranged short linear leaves
• disjunct petiolate leaves
How to Identify Eucalyptus
• Leaves: Carefully examine the leaves of the tree. Eucalyptus has protracted and pointed leaves with leathery texture and flat sides. A closer look at the leaves, especially with a magnifying glass, will give you the opportunity to see the oil-secreting glands throughout the leaves.
• Branches: Closely observe the branches of the tree. Adult eucalyptus leaves are sickle-shaped, which alternate on the branches on which they grow.
• Flowers: Look for flowers budding from the branches. Eucalyptus flowers look like closed cups before they bloom and when they open, there are no petals but fluffy hair, which are actually flower stamens.
• Fruit: Explore the flower stems to look for fruit growth. Looking like a small, woody capsule, eucalyptus fruit grows until it splits open and ejects seeds.
• Bark: Touch the bark to determine its texture, which is usually tough and flaky. In most of the species, there is seasonal shedding of the outermost bark layer.
The amount of litter dropped by eucalyptus is huge. Eucalyptus litter is highly flammable and a fire hazard. This is because of rapid vaporization of oils that results in rapid ignition.
Inspection of Specimen
The process of identification begins with comprehensive external assessment in the field and ends with microscopic examination in the lab. Learning how to identify eucalyptus will be easy if the internal features of the plant are explored, which are relatively protected from outside elements and predators. It is easy to sample mallees, as the leaves and flowering structures are about a few inches tall and can be collected easily.
How to Choose Specimen
• Avoid using the largest or the smallest leaves as specimen; rather select typical leaves.
• Avoid using the fruit on the ground, as you never know whether they belong to eucalyptus genus.
• Avoid using those juvenile leaves to assess if you doubt their source, that is, whether they belong to eucalyptus genus.
It is natural to find a variety of juvenile leaves in a mixed species stand. Spend considerable time looking at both adult and juvenile growth in the stand. Further still, if you find difficulty in identification, then the last option is to grow the seedlings. Observe the seedling growth to identify the shape of the cotyledons and whether the leaves become disjunct in their juvenile days. Identify the shape of seedling leaves to see if they are stalked or stalkless.
Also take the plant height, the number of stems or trunks, the crown color and appearance into consideration. This will help you determine whether it is composed of juvenile or adult leaves. This will also help identify the general size of the leaves and whether the bark is rough or smooth.
Important Facts: How to Identify Eucalyptus
It is important to note that some eucalyptus species hardly develop true adult leaves; rather, they retain their juvenile leaf phase, with glaucous and rounded leaves.
• Adult leaves: The sickle-shaped adult leaves are arranged alternately on the branches, whose special glands contain volatile oils.
• Juvenile leaves: The grayish-colored juvenile leaves lie opposite to each other on the branches.
• Operculum: Operculum is a cap-like structure that protects petals and stamens at the bud stage. It is shed when the flowers open.
• Shape and size: Shape and size of pods also help in identifying species. Pods comprise innumerable seeds and some amount of infertile chaff. The seeds are larger and darker than the chaff.
For any kind of photographic record, always photograph trees early morning or late afternoon, though during winter, photography is the best if the sun is out so that the trunk or stems are in sunlight.