The parts of a plant most used in plant identification by the inexperienced plant observer (non-botanist) are the size, shape, buds, flowers, fruit, bark and leaves of a plant. The usefulness of these attributes for identification depends greatly on the plant being identified. The key to becoming good at identifying different plants is working out which attributes of the plant vary the most between different plants. For example, one of the most defining features of the different local Acacia (wattle) species is the size and shape of the leaves. For Eucalyptus, the fruits (gum nuts) will often vary greatly between different species, making this the most useful tool for identification. For many of the smaller shrubs and ground layer plants, it is the flowers which tend to be the most noticeable and varied feature. Despite these distinctions, it is often necessary to look at a combination of plant attributes to make a positive identification. Even then it can still be very challenging, especially if there are many species of the same genus in a particular area.
Thankfully, there are many excellent plant identification resources to aid with plant identification. Many of the plant identification resources available for use base their defining techniques on one or more plant properties. For example Ann Prescott’s It’s Blue with Five Petals uses flower colour as its defining feature.
Many of the resources tend to cover whole of South-eastern Australia, South Australia or the whole of the Mt Lofty Ranges. Opening a book of Australian Eucalypts, to discover that there are more than 500 species, can be quite daunting. Convenient for us there are only about 90 which are indigenous to South Australia and from these only about twelve which are indigenous to the Onkaparinga catchment area. For this reason it is better to have the most local resources possible to reduce the pool of possibilities.
See the recommended resources in the Identification of Local Indigenous Plants (Best of Catchment Connections) for some good local publications. Note that all of the referrals to vegetation in that activity is really only relevant to patches of remnant vegetation most often located on roadsides and in reserves. Many, if not most of the Australian natives historically used in amenity plantings in streetscapes and gardens are not local, but most often indigenous to Western Australia or the East Coast of Australia. Attempting to find a Western Australian native in a book about South Australian plants can be very frustrating! Stick to remnant patches for plant identification activities.
A good starting point for plant identification is to try to identify to genus level, as this is often very distinctive. Once students can confidently identify an Acacia, Eucalyptus, Hakea or Banksia, etc, identifying the species within that genus will seem a lot simpler.
Acacia: A widespread genus
Acacias (or Wattles) are the most widespread genus of Australian native plants. The Acacia genus is also indigenous to South Africa. Species within the Acacia genus are often best recognised by their leaf shape. Generally the Acacia genus is very robust and being of the LEGUMINOSAE family (legume), is able to improve soil nitrogen levels. It is used extensively in revegetation projects due to its ability to colonise areas of bare ground and recent disturbance. However this, resilience can also make them a formidable pest plant if they are introduced to areas outside their natural range.
Plants as resources for local wildlife
The buds, flowers, fruits and seed of our local native plants are generally the richest source of food for many of our visible wildlife such as insects birds and mammals. Many of us have observed Honeyeaters frequenting tubular flowers in suburban gardens, Yellow-tailed black cockatoos eating the seeds of a Banksia or groups of Parrots eating the flowers of Eucalypts and dropping the leftovers all over the ground. Unfortunately for these animals, plants do not produce the specific resources needed all year round. Many animals must travel to find enough resources. Historically, animals are probably well-accostomed to travelling for their food but modern times have no doubt made life harder through:
the loss of large tracts of the right kind of resources (vegetation) and
barriers in the landscape such as roads, fences and treacherous cleared landscapes where smaller animals have little shelter or protection from predators.
While we often associate spring with a flush of flowers and life, there are many plants which provide all-important resources throughout lean times in summer, autumn and winter. Sometimes the timing and duration of flowering will vary in an area due to seasonal factors such as rainfall, soil fertility and temperature. Learning when and where our vegetation provides the resources needed for wildlife can teach us a lot about why populations of species decline or explode.