Indonesia has recorded the identification of a new Rafflesia species from the forests of East Kalimantan. A research team from the National Research and Innovation Agency (BRIN) has designated the species as Rafflesia harjatii, with the findings published in the journal Sains Malaysiana on 12 January 2026.
The plant’s presence has been known since the 1980s within the forest area of PT ITCI Kartika Utama (ITCI-KU). In 2019, forestry researcher Tri Atmoko from the Ministry of Environment and Forestry reported its population, although its taxonomic identity could not yet be confirmed.
Formal species recognition requires rigorous scientific validation through detailed morphological examination and genetic analysis.
Further investigation was conducted in 2022 by a team led by Agus Susatya of the University of Bengkulu, in collaboration with BRIN researchers Ridha Mahyuni, Sudarmono, Dian Latifah, Willie Smits, and Arief Priyadi.
The results demonstrate that the flower exhibits distinct morphological traits and genetic characteristics that differ from all previously known Rafflesia species in Kalimantan, supporting its recognition as a new species.
Morphological Characteristics
Rafflesia harjatii grows in lowland dipterocarp forest at elevations of 325 to 329 meters above sea level. Like other members of the genus, it is a parasitic plant that depends on host vines of the genus Tetrastigma. The flower measures approximately 17 to 22 centimeters in diameter.
Morphologically, the species shows a unique combination of features. White blotches on the perigone lobes are relatively fewer in number but larger in size.
The diaphragm is thicker with a narrower opening. The internal ramenta are well developed and cylindrical, resembling small clubs. The inner disk displays protrusions that do not match descriptions of previously published species.
Compared with the four recognized Rafflesia species in Kalimantan, R. hasseltii, R. keithii, R. tuan-mudae, and R. pricei, R. harjatii lacks the so called window structures on the inner surface of the diaphragm and possesses only a single annulus, whereas the other species have two.
DNA analysis further confirms that the plant represents a genetically distinct lineage.
Endemic Status and Conservation Outlook
Based on preliminary assessment, Rafflesia harjatii is considered endemic to East Kalimantan, as it has so far been documented only in this region. Researchers have identified three subpopulations at the discovery site.
According to Ridha Mahyuni, human related disturbances remain relatively limited because the populations occur within a company managed conservation area. Nevertheless, natural threats such as high rainfall are identified as factors requiring continued monitoring.
The discovery has been welcomed by the Komunitas Peduli Puspa Langka (KPPL). The research team is planning further field surveys to determine population size more accurately and to map the species’ distribution in greater detail.
In addition to Rafflesia harjatii, BRIN has indicated that data on several other candidate Rafflesia species are currently being finalized, with formal announcements expected later this year.
