Garcinia gamblei P.S. Shameer, T.Sabu & N.Mohanan is an evergreen dioecious tree species of the family Clusiaceae, endemic to the southern Western Ghats of Kerala, India. It was described in 2017 as distinct from Garcinia pushpangadaniana because of its horizontal branches, sessile pale green flowers, staminodes either arranged in loose bundles or in five phalenges, five loculed ovary and stigmatic lobes, vertically grooved fruits with depressed apex and oblongoid seeds. Of the 37 Garcinia species in India, seven are endemic to the Western Ghats biodiversity hotspot. Two of these species are categorized as Critically Endangered, two as Endangered and one as Vulnerable on the IUCN Red List.

As G. gamblei is categorized as Data Deficient , we conducted five field surveys in the Ponmudi hills, the only known locality of the species, in Thiruvananthapuram, Kerala, during June 2021–March 2022. Of the 31 trees we located within an area of < 1 km², with girths of 20–150 cm at breast height, we found only three female and two male flowering trees, in the shola forest, an endemic, threatened ecosystem, at altitudes of 964–1,097 m. The trees produce a small number of flowers (range 3–300; male:female ratio 1:10) during November–February and fruits (each with 1–3 seeds) from June to September. We did not find any seedlings of the species.

Our field surveys and information obtained from local people suggest the potential threats to G. gamblei are: (1) the low number of reproductively active trees in the population, (2) the rarity of seedlings, indicating low recruitment, (3) strong winds during the monsoon season damaging the large branches of mature trees, (4) an increasing number of tourists and occasional forest fires, and (5) high seed predation.

(a) Female and (b) male flowers of Garcinia gamblei. Photos: Abinlal Kavungullachalil.

Measures are required to prevent the extinction of this rare tree species. Our preliminary studies indicate the seeds have high moisture content and delayed germination. At Jawaharlal Nehru Tropical Botanic Garden and Research Institute research is being carried out on propagation protocols (both sexual and asexual), population structure and ex situ conservation of G. gamblei. We are planning to collect seeds of G. gamblei for ex situ propagation and potential translocation of the species to the Botanical Garden and its natural habitat.