Key points
- By closely observing nature, people sometimes notice plants that are entirely new to science.
- Scientists collaborate to compare these plants with specimens found in the wild and preserved in herbaria.
- Through this collaborative process, researchers confirmed that the orchid species Adelopetalum argyropus is unique to Norfolk Island and identified two new Adelopetalum species on Lord Howe Island and mainland Australia.
Imagine discovering a tiny orchid perched on a tree branch in a forest. It resembles an orchid you’ve seen before, but something is subtly different. Could it be a new species that hasn’t yet been named or described by science?
How would you find out?
Step 1: Take it home
Can you take home a rare plant?
Yes, if you’re a botanist with a collecting permit and home is a herbarium.
Dr Heidi Zimmer is an orchid researcher at the Australian National Herbarium (ANH) in Canberra.
While visiting Norfolk Island National Park with botanist Dr Mark Clements, local knowledge and expertise of the Norfolk Island National Park team including Joel Christian, Mel Wilson and Allie Andersen helped the scientists locate an area thought to be home to a tiny and little-known orchid. In the late afternoon light, Mark spotted it growing on a small tree branch.
Something about the orchid looked a little different, so Heidi collected a sample to take home to ANH.
Step 2: Form a team
The orchid from Norfolk Island was obviously a species of Adelopetalum – at least that was obvious to experts like Heidi and Mark. But while Norfolk locals would be familiar with the tiny plant, scientists were keen to determine if it was a known species or a new one.
Heidi and Mark were joined by a team of scientists, including lead researcher David Jones, a retired botanist who formerly worked at ANH.
“This was a wonderfully collaborative project with folks from Lord Howe Island and Norfolk Island, and Australian botanists and taxonomists all working together,” Heidi said.
Step 3: Search it up
When a botanist suspects a species is new to science, it’s the start of a long journey to find out.
The team began a search to compare the orchid from Norfolk Island with:
- orchid species described in scientific journals
- orchid specimens held in the Australian National Herbarium (there are approximately 75,000!)
- orchids specimens held in other herbaria in Australia and overseas. In the past, botanists had to travel to other herbaria or request specimens be loaned by mail. Today, many herbaria are digitising their collections and making the photos available online.
The research revealed that the orchid species known as Adelopetalum argyropus wasn’t one species that lived across Norfolk Island, Lord Howe Island and continental Australia. It was three distinct species.
“Firstly, we recognised that the Norfolk Island species was different because the flower did not have a yellow labellum – no giant bright yellow tongue,” Heidi said.
“We looked at living plants, dissected flowers mounted on cards and herbarium specimens. The difference was pretty clear, even for a taxonomist in training like me.”
Step 4: Name it!
The three orchid species shared the name Adelopetalum argyropus. So which species would get to keep the name?
Whichever was first.
“Yep, that’s a rule in taxonomy, not just for who gets the front seat in road trips,” Heidi said.
Adelopetalum argyropus was first described from Norfolk Island in 1833 (as Thelychiton argyropus, but that’s another story because it was later moved into a different genus). As a result, the orchid from Norfolk Island kept the species name.
The team named the other two orchids A. howense and A. continentale. (You can tell from the names which is which!)
“That there are three separate species on Norfolk Island, Lord Howe Island and continental Australia makes sense because they clearly cannot readily interbreed,” Heidi said.
“That said, the orchids spread to those islands somehow. It was probably that marvellous dust-like orchid seed, which is so fine and dusty it can be carried on the wind to far away places.”
Step 5: Describe it
Naming a species is only a small part of the scientific process of describing a new species.
Researchers must also publish a scientific paper in a peer-reviewed journal. The paper describes the botanical features of new species and may include photos, microscopy images, scientific drawings and DNA results.
To give you a glimpse of the species description for the orchid on Norfolk Island, the paper notes it has: "Pseudobulbs broadly oblong to obconical or turbinate (similar to a cupcake, “poculum crustulam simile”), 5.0–10.0 × 4.0–6.0 mm, margins with 4–5 weakly angular ribs, surface shallowly grooved, scurfy from remnants of fugacious bracts, apex truncate with shallow to deep depressions."
Step 6: Assess it
Orchids are one of the plant families most at risk of extinctions. Many species grow in single locations or have very small populations.
“The purpose of naming and describing new orchid species is to build a checklist of Australian orchids so people can conserve them,” Heidi said.
“We think there are risks for these three new species. This is because the species on Norfolk and Lord Howe Islands are both confined to small islands and the one on continental Australia was badly impacted by the 2019–2020 bushfires.”
The team's research paper ‘Characterisation of Adelopetalum argyropus (Orchidaceae; Malaxideae) with the description of two related new species and two new combinations’ was published in the journal Phylotaxa, with lead author David Jones.
This research was partly funded by the Australian Network for Plant Conservation, with support from the Plant Conservation Team at the San Diego Zoo Wildlife Alliance, and the Australian Orchid Foundation.
The Australian National Herbarium is part of Centre for Australian National Biodiversity Research, a joint venture between Parks Australia and CSIRO.