SA Department for Environment and Heritage

As the scientific world celebrates the 150th anniversary of Charles Darwin publishing his theory of evolution, researchers at the State Herbarium of South Australia are continuing to map evolutionary changes in our state's flora.

'The Origin of the Species' was first published by Darwin on 24 November 1859. This book outlined his theory of plant and animal populations evolving over time, through natural selection, into new and different species.
In finalising his theories, Darwin consulted with a botanist who had seen evolutionary changes in flowers. Today, botanists at the State Herbarium of South Australia - part of the Department for Environment and Heritage - are able to track these evolutionary changes in the plants of our state.

Graham Bell, Acting Chief Botanist of the State Herbarium of South Australia, has been working with the herbarium for nearly three decades and knows the importance of the collection.
"It's so important to know what flora we have in South Australia," he said. "If we don't know about it or have a name for it, we can't protect and conserve it.

"The State Herbarium collection can be used to monitor how plant species have evolved and adapted. Each plant sample in the collection is identified and the date and location from which it was taken is mapped.
"However, plant species aren't constant. They can change over time or over a large geographic area due to a change in the environmental conditions. The same species grown in different climates can change over time until two distinct species emerge."

It was this type of variation Darwin identified in plants and animals, calling it natural selection in 'Origin of the Species'.

In the last 20 years, over 1,000 new names have been added to the list of South Australia's flora. Most of this increase is due to discovery of new species and reclassification of old species. Sadly, about one-third of the increase is also due to weed varieties being introduced within the state.

The state collection came together in the 1950s when personal and institutional herbaria were centralised at the Adelaide Botanic Garden. Since then, the collection has continued to expand and today the number of samples in the herbarium totals almost one million.

The State Herbarium provides the basis of knowledge for many areas of plant science. Research being performed through the collection includes measuring the effects of climate change on plants and marine algae, conservation of threatened species and the response of fungal species to fire.

The State Herbarium will not stop growing in the future. A continual collection of samples will help the collection grow and allow for scientists to continue mapping the evolution of South Australian flora.