Earlier this year, I found this beautiful but obscure Malesian plant while escorting a gardening tour of Vietnam. How can it be identified?
Malesia is a biogeographical region consisting of East Timor, Indonesia, Malaysia, Singapore, Brunei and the Philippines. Its tropical flora is even more diverse than Australia’s.
When I first visited Vietnam you could see the influence of the French empire behind some of the plants introduced there from tropical west Africa, Madagascar and New Caledonia.
I have a working knowledge of 15,000 species; I know what they look like and I have grown them. I identify an average of two plants a day from questions submitted to this website and my public Facebook page (they are followed in 109 countries). But sometimes an unusual plant turns up and one beauty had me stumped…
The flowers resembled Solandra – the Solanaceae family – but the fruit made me think of mangosteen – the Clusiaceae family. That’s when I realised a trip to the Queensland herbarium was necessary; they have the botanical keys to solve the identity problem.
A herbarium collects preserved plant specimens, usually as pressed, dried and mounted samples with their associated records for scientific study. The Queensland Herbarium has over 800,000 plant specimens starting from collections made during Sir Joseph Banks’ expeditions to specimens delivered yesterday.
This herbarium offers a public identification service, allowing Queenslanders to submit specimens of photos of plants for identification by botanists who answer thousands of such requests each year.
What is needed to make a positive identification?
1. Ideally, provide pressed, dried plant specimens about the size of an A4 or A3 page. Australian quarantine regulates the import of plant material, so I emailed my photos;
2. Specimens (or images) of the reproductive parts of the plant: flowers, fruit, seed;
3. Images of the whole plant showing its growth form;
4. The leaf shapes and how leaves are placed on the stems (the arrangement);
5. Bark (if present);
6. Location information. If it is a wild specimen, describe the plant community and the soil type. My mystery plant is a well established evergreen shrub growing in fertile, deep red loam in the moist, warm temperate climate of Da Lat.
The ID process
When I arrived, it was Dr Laura Simmons’ turn to staff the public ID counter. Dr Simmons specialises in rare or threatened native plants, but botanists have a roster to work on the ID counter.
Laura used an on line key and by observing information from points 1-6 illustrated by my photos it was possible to confirm my plant belongs in the Gentianaceae botanical family.
Next, Laura used another on line key to work out which genus in Gentianaceae it belonged to. Keys ask a series of questions to which there is a simple yes or no answer. These answers guide you step by step to the result:
* Leaves with stalks (yes);
* Leaf edges entire (yes);
* Flowers produced in clusters from shoot tips (yes);
* Flowers deeply divided and funnel-like with a long tube (yes);
My mystery plant turned out to be: Fagraea ceilanica
Botanical names can change, a consequence of our deepening knowledge of plant evolutionary relationships. When I checked the list of name changes for this plant I noticed it was once known as Solandra oppositifolia. That was reassuring, as I had instinctively thought it might be a Solandra.
Turning to The Flora of China we read that Fagraea ceilanica is a tropical evergreen shrub, or epiphyte, or a tree to 15m tall. A plant of dense forests growing over limestone.
Looking at the records of two different pressed specimens of Fagraea ceilanica we had a more complete distribution of this plant: it originates from China, Taiwan, Sri Lanka, SE Asia, Indonesia, New Guinea and the Philippines.
The Queensland herbarium offers up to ten specimens identified for free for members of the public each year, as well as information and advice on Queensland’s plant species and vegetation, including information about distribution, weediness, toxicity and conservation status.
Director, Seed Savers’ Network Inc.
Patron, National Toxics Network Inc.
16th December 2019