A herbarium is an evolving collection of dried plants, fungi and algae, but it's also a time capsule. Each specimen has a story: what is it, where and when was it collected, and by whom?

Perhaps it was collected by a famous 18th century naturalist while shipwrecked on the Great Barrier Reef. Or maybe it is one of the few records of an extinct species. Or it contributed to a major scientific discovery.

With an estimated 150,000 specimens, the University of Melbourne Herbarium (MELU) is the largest university herbarium in Australia, and its online collection is now freely available to the public for the first time.

We asked the University of Melbourne Herbarium curator, Dr Jo Birch, to share five stories from this fascinating collection.

Endeavouring to collect lots of plants

Botanist Sir Joseph Banks famously accompanied James Cook on the HMS Endeavour, where he and Swedish naturalist Daniel Solander collected plant specimens from South America, Tahiti, New Zealand, and the east coast of Australia.

Most of this collection is housed at the Natural History Museum in London, but two samples he collected in 1770 have made their way to the University of Melbourne Herbarium.

"It is typical for duplicate sets of specimens to be collected in the field," says Dr Birch.

"These two specimens, Sphaeromorphaea australis (previously called Epaltes australis) and Epaltes cunninghamii, both from the Asteraceae or daisy family are likely from one of the duplicate sets, with originals retained at the Natural History Museum.

"These species have since been collected at many locations around Australia, but Banks' collection site is unknown because the original labels are not retained with these specimens.

"However, both species are known from the area around Cooktown, where Banks and Solander spent eight weeks collecting more than 200 species then unknown to western science while repairs were made to Cook's ship the Endeavour, which had been badly damaged on the Great Barrier Reef.

"These samples may have been collected during that time."

"The only time this plant has been collected"

The specimen of Maiden's Bush-Pea (Pultanea maidenii) held in the University of Melbourne Herbarium is one of a handful of specimens collected by H. B. Williamson in 1906 in the Grampians in western Victoria. This was sadly, as the annotation on the collection label states, "the only time this plant has been collected".

In fact, this was possibly the last time a living specimen was ever seen, and the species is now listed as extinct.

"A quick check of the Australasian Virtual Herbarium shows me that there are 11 other specimens of this species collected by Williamson in Australian herbaria," says Dr Birch.

"This shows the value of online herbaria, as finding this information in the paper age would have been a significant undertaking."

Mr Williamson was the honorary keeper of the University of Melbourne Herbarium from its founding in 1926 through to 1931; he and herbarium founder Professor Alfred Ewart made significant contributions to the collection.

In 1930, Mr Williamson and Professor Ewart collaborated on the publication of the book Flora of Victoria, published by Melbourne University Press - the first comprehensive record of Victoria's plant species.

Then and now – the Grimwade Plant Collection

Between 1938 and 1939, botanist Percival St John was commissioned by the philanthropic Grimwade family to make a collection of plants from the Mt Buffalo plateau in north-eastern Victoria.

In 2006, the Grimwades, through the Miegunyah Foundation, commissioned University of Melbourne botanists to move this collection from the Mt Buffalo Chalet to the University's Herbarium, where it could be properly conserved and databased, and to re-survey the area.

Dr Alison Kellow, Dr Mike Bayly and Professor Pauline Ladiges made three trips to Mr Buffalo, collecting 226 species of plants that now form the Mt Buffalo Miegunyah Collection.

"The revised list of vascular plants from Mt Buffalo National Parks now includes 617 species, subspecies and varieties, with 129 new additions to the list following the 2006 study," says Dr Birch.

"Continuing their support for the collection, the Russell and Mab Grimwade Miegunyah Fund is funding the production of high-resolution images of the herbarium's culturally significant specimens, including the original specimens made by Percival St John, which are available in the online collection."

Some plants like it hot and stinky

The titan arum from Indonesia is famous for two things: it produces the largest flower in the world, and the flower smells bad - like rotting flesh.

"Australia has a related group of plants called Typhonium, and they too are super-stinky," says Dr Birch.

PhD student Tom Sayers and his supervisor Dr Rebecca Miller are trying to understand the plant-pollinator interactions of these plants.

"The flowers attract insects by mimicking the odour and appearance of dung or carrion. The flowers also have the remarkable ability to raise their temperature up to 15°C above ambient, using a process called thermogenesis," says Mr Sayers.

"These plants only flower for two days at a time, so field work is a challenge. We spend long days in the field to collect the plant samples."

Dr Birch says it's important that Mr Sayers' specimens are preserved in the herbarium, so other scientists can go back to the original herbarium specimen and confirm the identities of the species that he collected.

"And with the digital collection they can do this from anywhere in the world. Each of our images is around 275 MB in size, so the user can see even the finest detail such as leaf hairs and nectar glands on the specimens."

New technology meets old

In the high-tech world of modern science, herbaria may seem like an anachronism, but they are still as important as ever.

PhD student Cat Clowes, along with her supervisor Dr Mike Bayly and collaborators, recently sequenced the complete chloroplast of the Australian shrub Spyridium parvifolium (Dusty Miller) - all 161,012 base pairs of it.

"Over the course of her research, Cat has collected more than 150 herbarium specimens that are now housed in the University of Melbourne Herbarium, ensuring that the specimens she used for her DNA extractions are preserved for future studies," says Dr Birch.

"While Cat collected fresh-leaf material for DNA extraction, DNA can also be extracted from dried herbarium samples and the University of Melbourne collection is frequently used for this purpose."

Opening the virtual doors

Dr Birch says herbaria play an important role in documenting biodiversity; but University of Melbourne staff and students (including approximately 30 volunteers who work in the collection annually) ensure that the biodiversity data are accurate and accessible.

The Herbarium sits in the corner of the old Natural Philosophy building in Parkville, but increasingly visitors are accessing the collection online.

"There are more stories in the collection than our herbarium staff and dedicated team of volunteers could ever tell, but by making the collection online, we hope others will find some overlooked gold in the collection," she says.

The public and other researchers can now access the University of Melbourne Herbarium Collection Online, where high-resolution images of 9360 MELU herbarium specimens.

Since 2014, the herbarium has also been contributing specimen data to the Australasian Virtual Herbarium, which makes public the data of more than 8 million plant, algae and fungi specimens kept in Australian and New Zealand herbaria.

"In the last 12 months, 652,259 data records from our specimens have been downloaded from the Australian Virtual Herbarium, so there is a need for these data," says Dr Birch.

"Our online collection gives people from around the world the digital key to virtually explore and discover the biodiversity held within our Herbarium"

Banner image: University of Melbourne Collection Online.