Orchid that was presumed extinct, new liverwort species among plant discoveries recorded in 2021
More than half of the nine botanical discoveries recorded in Singapore in 2021 were made in Bukit Timah Nature Reserve.
SINGAPORE: A small ground orchid that was presumed extinct in Singapore and a species of liverwort that is "new to science" were among the botanical discoveries recorded in the country in 2021, the National Parks Board (NParks) said on Monday (Jan 10).
A total of nine such plant, fungal and algal discoveries were recorded last year: One new species, five new records of species that have not previously been seen in Singapore, and three rediscoveries of species that have not been seen or collected for at least 30 years.
More than half of these discoveries were made in Bukit Timah Nature Reserve, said NParks.
A small ground orchid known by the scientific name Hetaeria oblongifolia was among the rediscovered plants.
It was found in Tengah Forest more than 120 years after the last specimen of it was collected by Henry Nicholas Ridley, the first scientific director of the Singapore Botanic Gardens, said NParks.
During an environmental baseline study at Tengah Forest in 2020, scientists collected "a patch of herbs that superficially resembled the ornamental Dracaena species".
"On closer examination, several inflorescences in bloom revealed that these plants belonged to a species of ground orchids," said NParks.
Specimens were sent to the Herbarium of the Singapore Botanic Gardens, where the plant was identified as Hetaeria oblongifolia.
Previously considered extinct in Singapore, the orchid is now assessed to be critically endangered, as there are "very few plants" left, said NParks.
"As part of efforts to conserve this species, some of the plants have been collected and planted in the Gardens' orchid nursery, where propagation by rhizome cuttings seems to be effective," it added.
Tengah Forest is designated for redevelopment in the Urban Redevelopment Authority's Master Plan, and is set to provide about 42,000 new homes when fully developed.
Apart from Tengah Forest, two other rediscoveries were recorded in 2021 at a reclaimed site in Tuas and at Bukit Timah Nature Reserve.
Three rediscovered plants in Singapore
Three plant rediscoveries were recorded in 2021 - this is when species that have not been seen or collected for at least 30 years are found again.
1. Dodonaea viscosa
A flowering and fruiting population of this plant was discovered during a survey at a reclaimed site in Tuas in 2019. The population consisted of more than 10 individual plants about 1.5m tall. In Singapore, the species is presently only found in this single location in Tuas.
The plant is now assessed as nationally critically endangered, after previously being considered extinct. In addition to propagation efforts by NParks, more than 10,000 seeds have been collected and stored in the Singapore Botanic Gardens Seed Bank.
The species is usually found in coastal vegetation and along sandy beaches, and can be a shrub or small tree of up to 8m in height.
2. Amanita sculpta
This fungus was first collected from the Bukit Timah Nature Reserve in 1939, and was not seen or collected for more than 80 years until it was rediscovered in the nature reserve in 2020.
"This is the first time the fungus has been observed growing near the base of a Shorea leprosula, which further supports the observation that dipterocarp trees have symbiotic relationships with many genera of fungi, including other Amanita species," said NParks.
Such relationships are important to the growth and regeneration of dipterocarp forests, as they help in the establishment and growth of dipterocarp seedlings, it added.
3. Hetaeria oblongifolia
This small ground orchid, measuring 14cm to 20cm, was rediscovered during an environmental baseline study in Tengah Forest in 2020.
Before that, the last specimen was collected in Bukit Timah Nature Reserve in 1897 by the Singapore Botanic Gardens' first scientific director Henry Nicholas Ridley more than 120 years ago in 1897.
This is considered a critically endangered species as there are currently very few plants in Singapore, said NParks.
NEW LIVERWORT SPECIES
The new species, Gaolejeunea hoi, is a tiny plant measuring no more than 1cm long and 1mm wide. A species of liverwort, it grows on tree bases and exposed roots in the forests of Bukit Timah and Nee Soon.
The plant was first collected at Bukit Timah Nature Reserve during a survey of the area from 2015 to 2017.
Initially, researchers were unable to categorise it into any known genera of the Lejeuneaceae family in Singapore, which account for about half of all liverwort species reported in the country, said NParks.
"Upon further research, it was confirmed that this is a new species record to science and a second species in the genus Gaolejuenea that was formerly considered to be endemic to China," the authority said.
The new liverwort species is currently considered endemic to Singapore, added NParks. It is named after Dr Boon-chuan Ho of the Singapore Botanic Gardens, who collected the first specimens of it.
Five new records of plants in Singapore
Singapore added five species of plants that have not previously been recorded in the country in 2021.
1. Lepidogyne longifolia
This plant from the Orchidaceae family is considered native to Singapore and is also known to be native in parts of Johor and Sumatra.
A small population was first discovered in Bukit Timah Nature Reserve in 2019, consisting of likely only three individual plants. In Singapore, the plant is found in the shade of the forest understorey and in the fully saturated soil of a freshwater swamp.
2. Ptyssiglottis kunthiana
This plant, of the Acanthaceae family, is considered native to Singapore, where it grows in humid shade among large natural boulders in the primary forest of the Bukit Timah Nature Reserve. It is also known to be native in parts of Johor and Sumatra.
Although the plant is assessed as a species of least concern globally, there is only one small population found in Singapore, consisting of only 100 to 200 individual plants with a restricted distribution of about 20m by 70m.
3. Thysananthus ciliaris
This liverwort species was discovered in 2020 growing among other tiny plants on the buttress of a Terminalia subspathulata heritage tree, during a survey in the Singapore Botanic Gardens. The plants form in a mat with each shoot reaching up to 3cm long, and 0.8mm to 1.5mm wide.
NParks said it is a "rare and poorly known species from Southeast Asia", with just five verified collections recorded. It is globally endangered and nationally critically endangered.
4. Ficus subulata
This species was collected several times between 2005 and 2021 from secondary forest on Pulau Ubin, but was only recently identified as the genus Ficus is particularly large and complex, said NParks. It has not yet been found on mainland Singapore.
It can be found as a creeper, growing in or on rocks, as a shrub or as a root climber growing to about 8m high on a host tree.
A widespread species considered native to several countries in the southern and eastern regions of Asia, this plant is assessed as a species of least concern globally, and critically endangered nationally.
5. Visia cylindrocellularis
Formerly thought to exist only in Pahang, this is the only known freshwater red algae species in Singapore. It was discovered in 2018 in a forest stream of Bukit Timah Nature Reserve and is assessed as nationally critically endangered.
The discovery extends the distribution of Visia cylindrocellularis considerably southwards, said NParks, adding that future research will contribute to a better understanding of the diversity and distribution of this group of red algae.
With the botanical discoveries recorded in 2021, a total of 124 new plant species, new records and rediscoveries in Singapore have been published over the past five years, said NParks.
Minister for National Development Desmond Lee said the discoveries were possible due to in-depth field surveys and taxonomic research led by the Singapore Botanic Gardens, supported by local and international collaborators.
He highlighted the work of the Gardens' Herbarium, which documents and preserves records of local and regional flora diversity, as well as the Seed Bank and Micropropagation Laboratory, which store and propagate the seeds of plants in the region, including extremely rare native plant species from Singapore.
"These efforts to conserve and continuously update our understanding of the flora diversity in Singapore will help to better inform our conservation strategies to safeguard Singapore’s key habitats and rich biodiversity, thus achieving a more ecologically and climate resilient City in Nature," Mr Lee said in a Facebook post.
"The work will contribute to the Gardens' ongoing Flora of Singapore project, which aims to catalogue and describe Singapore's plant diversity."