Lophopetalum tanahgambut is a large top canopy tree growing to 40 m tall, with a trunk diameter at breast height (dbh) of up to 1.05 m.
Lophopetalum tanahgambut and its knee roots system. Image credit: Randi et al., doi: 10.11646/phytotaxa.573.1.7.
The newly-identified tree species belongs to the genus Lophopetalum in the cosmopolitan family Celastraceae.
This genus includes almost 20 currently recognized species native to India, Bangladesh, Indonesia, Cambodia, Laos, Malaysia, Myanmar, Nepal, New Guinea, Philippines, Thailand, Vietnam, Australia, and the Andaman Islands.
“Within the Celastraceae family, the tribe Lophopetaleae includes three paleotropical genera with winged seeds that lack an aril: Kokoona, Lophopetalum and Peripterygia,” said National University of Singapore’s Environmental Research Institute researcher Agusti Randi and colleagues.
“The largest genus is Lophopetalum with 19 species defined by the inner surface of the petals with various appendages (hence the generic name from the Greek for crest: lopho-), as well as the 5-merous bisexual flowers with stamens inserted on the disk, a 3-locular ovary, and 3-angular capsular fruits with the wing surrounding the seed.”
“The genus is closely related to Kokoona, with which it shares the 3-angular fruit and winged seeds, but Kokoona has the seeds attached at the base and an apical wing.”
“Lophopetalum extends from India through to northern Australia but species diversity is centered on western Malesia, and seven of the 19 accepted species have been reported from the Indonesian island of Sumatra, but all of them range extensions from species described from material from Borneo, India or Peninsular Malaysia.”
Named Lophopetalum tanahgambut, the new species is only known from peat swamp forests of the Indonesian island of Sumatra.
“Peat swamp forests are known for their unique nutrient poor, carbon rich and wet conditions which require specific adaptations to survive in,” the researchers explained.
“These habitats, however, remain poorly studied and have undergone extensive conversion to agriculture with only 11% of undisturbed swamp forest remaining and with other areas degraded and still undergoing conversion to agriculture.”
Lophopetalum tanahgambut grows up to 40 m tall and has a dbh of up to 1.05 m.
Its knee roots system is wide, up to 15 m around the tree, raised to 1.5 m high from the ground surface.
Its bark is smooth, cracked longitudinally to flaky, light to dull gray, or milky white. The inner bark is pinkish orange to pale reddish brown; sapwood cream.
“The species is the only known Lophopetalum tree with 3-4 leaves in a pseudoverticillate arrangement,” the scientists noted.
Lophopetalum tanahgambut was observed flowering during February-April, and fruiting in April-June.
“We’ve observed many trees in various life stages (seedling, sapling, pole to large tree) in the wild, and the pseudoverticillate leaves are consistent,” the authors said.
“Opposite (or subopposite) leaves as usually found in the genus but does not occur in this new species.”
“On older branches we sometimes found opposite leaves but usually there is also a leaf scar slightly below them indicating they are not oppositely arranged from the beginning, but shift in position as the branchlets mature.”
“If a twig is 3-4 angular depends on the number of leaves at a node, and this is clearly visible when the twigs are still young.”
The researchers recommend that the new species should be categorized as Critically Endangered.
“Lophopetalum tanahgambut grows in relatively undisturbed lowland peat swamp forest, which is protected by voluntary commitment of the concession as a conservation and retirement area,” they said.
“More extensive collecting in the wider area may reveal otherwise, but for now we must assume a small population size and a restricted distribution in Sumatra.”
“While overall, undisturbed peat swamp forests have declined and under threat across Southeast Asia, and most remaining peatlands are converted to agriculture or degraded due to drainage.”
The team’s paper was published in the November 17, 2022 edition of the journal Phytotaxa.
_____
Agusti Randi et al. 2022. Lophopetalum tanahgambut, a new endemic giant tree species from peat swamp forest of Sumatera, Indonesia, with the first pseudoverticillate leaf arrangement in genus Lophopetalum (Celastraceae). Phytotaxa 573 (1); doi: 10.11646/phytotaxa.573.1.7
Source link: https://www.sci.news/biology/lophopetalum-tanahgambut-11409.html
