A New Flower in the Wet Rocks
Discovering Sri Lanka’s Kitulgala Balsam
A newly described plant from Kitulgala highlights the remarkable – and often overlooked –
diversity hidden within Sri Lanka’s specialised wet-rock habitats.
Sri Lanka’s forests continue to reveal botanical surprises. Even in landscapes that have been visited, studied and explored for generations, small and highly specialised habitats can still harbour species that have remained unknown to science.
One such discovery has emerged from Kitulgala, where researchers have described a new species of balsam, Impatiens yakandawalarum. Found growing on a continuously wet rocky slope at Manna Kathi Ella, the species represents a distinctive addition to Sri Lanka’s already remarkable diversity of Impatiens, commonly known as balsams.
The research, published in the Ceylon Journal of Science in 2026, describes the plant based on its distinctive morphology, habitat and comparison with other recognised species. The discovery also brings attention to a more difficult question: how many specialised habitats and species remain undocumented across Sri Lanka?
From a photograph to a species new to science
The story of the Kitulgala Balsam began with photographs of an unusual Impatiens population. Those observations prompted field investigations at Manna Kathi Ella in Kitulgala, Kegalle District, in July 2026.
Researchers found plants growing on a wet rocky slope beside the trail leading to a waterfall. Detailed examination of living plants, preserved material and herbarium specimens eventually established that the population represented an undescribed species.
The research team included Bhathiya Gopallawa, Sandali Hapuarachchi, Chathura Jayathissa, Salani Gunarathna and Peshala Karunarathna. The type specimen was collected at Manna Kathi Ella at approximately 173 metres above sea level and deposited at the National Herbarium in Peradeniya.
The species was formally named Impatiens yakandawalarum.
Its name honours Professors Deepthi Yakandawala and Kapila Yakandawala for their contributions to plant taxonomy, systematics, forestry, conservation and botanical research in Sri Lanka.
A proposed common name for the species is Kitulgala Balsam.
What makes the Kitulgala Balsam different?
At first glance, a small flowering plant growing among wet rocks may not appear particularly unusual. But closer examination revealed a combination of characteristics that separates I. yakandawalarum from its closest Sri Lankan relatives.
The plant is a lithophytic herb, meaning it grows on rocky surfaces. It reaches approximately 10-35 centimetres in height and has a fleshy underground storage organ that is globose to subglobose in shape. Its leaves are glabrous, while its flowers are pink to light purple.
Perhaps the most striking feature is found in the flower.
The lower sepal is completely ecalcarate, meaning that it lacks the spur normally associated with many Impatiens flowers. It is navicular in shape and contains a distinctive linear series of purplish-pink spots on its inner surface.
The absence of a floral spur is particularly significant because spur morphology is an important characteristic used in identifying and classifying Impatiens species. Complete spur loss is relatively uncommon outside certain lineages.
In I. yakandawalarum, this absence was not simply observed in one unusual flower. Researchers found the ecalcarate condition consistently across multiple individuals in the known population, with no short, vestigial or concealed spur detected.
A plant adapted to a very particular place
The Kitulgala Balsam is not a generalist plant growing across a broad range of environments.
It appears to be closely associated with a highly specialised microhabitat: continuously wet rock surfaces influenced by water seepage. The plants grow in shallow accumulations of soil and organic matter within rock depressions and crevices.
This is important because specialised habitats can support highly specialised species. They may occupy only a tiny portion of the wider landscape, yet contribute disproportionately to local biodiversity.
The researchers recorded associated plant species including Utricularia striatula, Sonerila silvatica, Humboldtia laurifolia and Diospyros insignis.
The Kitulgala Balsam is currently known only from its type locality at Manna Kathi Ella, at approximately 173 metres above sea level. However, the researchers caution that surveys of comparable seepage-fed rock habitats remain incomplete, meaning its actual distribution may be wider than currently known.
That uncertainty is significant. The plant may be extremely rare – or researchers may simply not yet have found all the places where it grows.
More than 1,000 plants – but still highly vulnerable
An interesting aspect of the discovery is that rarity does not necessarily mean only a handful of individual plants.
The known population contains more than 1,000 individuals, with approximately 50-100 flowering individuals observed during the July 2026 survey. However, the researchers caution that the number of mature individuals could not be reliably estimated because plants at different developmental stages were not systematically distinguished.
The population’s vulnerability comes instead from its extremely restricted habitat and distribution.
At present, the species is known from a single locality. Its calculated area of occupancy is only 4 km², and the researchers were unable to calculate its extent of occurrence because only one locality is currently known.
This combination of restricted distribution and habitat vulnerability led the researchers to make a preliminary assessment of the species as Critically Endangered under IUCN Criterion B2ab(iii).
When a trail becomes a conservation concern
The location of the Kitulgala Balsam creates an unusual conservation challenge.
The population occurs beside a public trail leading to a waterfall. While this makes the species potentially accessible to visitors, it also places its habitat directly alongside human activity.
During field observations, researchers found evidence that some plants had been removed from their habitat. The study also identifies continued disturbance, possible future trail expansion and changes to water seepage as potential threats.
For a plant dependent on a continuously wet rock surface, even seemingly small changes to the local environment could matter.
If the flow or availability of seepage water changes, the microhabitat itself could become less suitable. Likewise, physical disturbance of the rocks, surrounding vegetation or shallow organic material could affect the conditions on which the species depends.
This illustrates a broader conservation reality: protecting biodiversity does not always mean protecting a large forest area alone. Sometimes, it means protecting a tiny rock face, seepage zone or patch of habitat that supports a species found nowhere else.
A glimpse into Sri Lanka’s hidden balsam diversity
The discovery also adds to the growing understanding of Sri Lanka’s Impatiens diversity.
The research notes that Sri Lanka currently has 27 recognised Impatiens taxa, including 18 endemic species and three endemic subspecies. These plants occur across environments ranging from lowland wet forests to montane vegetation, often occupying specialised habitats such as shaded stream banks, seepage zones, forest embankments and permanently wet rock surfaces.
Recent descriptions of other new Impatiens species have already suggested that the island’s balsam diversity is not completely documented.
The Kitulgala discovery reinforces that point.
It suggests that looking for biodiversity cannot simply mean surveying large, obvious habitats. Species can be hidden within extremely small ecological niches, and their discovery may depend on careful observation of places that might otherwise appear insignificant.
What comes next?
There are still many unanswered questions about Impatiens yakandawalarum.
Researchers have observed the species for only a limited period, and its full flowering and fruiting period remains unknown. The longevity of individual plants has also not yet been confirmed. Although the fleshy underground storage organ may have a role in allowing the plant to persist through unfavourable periods, this has not yet been established.
Molecular research is also underway to determine the species’ phylogenetic placement and investigate whether the loss of the floral spur evolved independently in this lineage.
Perhaps equally important will be further field surveys.
Comparable seepage-fed rock habitats around Kitulgala and elsewhere in Sri Lanka remain incompletely surveyed. Future work could determine whether the Kitulgala Balsam occurs beyond its currently known site – or whether the population truly represents a species restricted to one exceptionally small habitat.
Protecting what we are still discovering
The discovery of Impatiens yakandawalarum is more than the addition of another name to Sri Lanka’s botanical catalogue.
It is a reminder that the island’s biodiversity is not confined to its most famous forests, wetlands and wildlife destinations. It can also exist in a narrow band of continuously damp rock, in shallow organic matter, beside a trail leading to a waterfall.
Such discoveries change how we see familiar landscapes.
A rock face that might appear ordinary to a passing visitor can be the entire known home of a species new to science. A small flowering plant can represent an evolutionary story that researchers are only beginning to understand. And a popular trail can simultaneously provide access to nature while creating pressures that need to be carefully managed.
For the Kitulgala Balsam, the immediate challenge is therefore not simply discovering where it occurs, but ensuring that the specialised habitat on which it depends remains intact.
The researchers conclude that the species’ restriction to a single locality highlights the need for both in-situ and ex-situ conservation measures.
As Sri Lanka continues to document its natural heritage, discoveries such as the Kitulgala Balsam offer an important lesson: there may still be much more biodiversity waiting to be found – but discovering it is only the first step. Protecting it is the greater challenge.
From an unusual flower growing on a rain-soaked rock surface to the discovery of a new endemic species, Bhathiya Gopallawa shares the story behind the discovery of Impatiens yakandawalarum, also known as the Kitulgala Balsam. He discusses the challenges of identifying this distinctive, completely spurless balsam, the importance of its specialised habitat, and why protecting even the smallest ecosystems is vital to safeguarding Sri Lanka’s unique plant biodiversity.
Q: The study was initiated after photographs of an unusual Impatiens population were submitted and followed by field investigations. What was it about those initial observations that caught your attention?
A: The flower colour caught my attention first, but more importantly, one lateral view appeared to show the absence of a spur. The image was unclear, but it was unusual enough to raise doubts and encouraged us to investigate the population in the field.
Q: What were the most challenging aspects of identifying and formally describing the species?
A: The flowers resemble Impatiens thwaitesii, while some vegetative characters are closer to I. janthina, so detailed comparisons with both species were necessary. Grey-Wilson had also mentioned apparently spurless forms of I. thwaitesii from Adam’s Peak, so we carefully checked available herbarium specimens and published descriptions to make sure this was not simply a variation of an existing species.
Q: For someone who isn’t a botanist, how would you describe the Kitulgala Balsam and what makes it different from other balsam species found in Sri Lanka?
A: The Kitulgala Balsam is a small pink to deep-purple flowering “Kudalu” that grows on wet rocky surfaces near Manna Kathi Ella. Its most remarkable feature is that the flower completely lacks the spur normally seen in Sri Lankan balsams. It is the first consistently spurless Impatiens species recorded from Sri Lanka.
Q: How does I. yakandawalarum differ from the visually similar I. thwaitesii and I. janthina?
A: It differs from I. thwaitesii mainly by its underground storage organ, glabrous leaves, smaller 2-3-flowered inflorescences and completely spurless lower sepal with characteristic internal purplish-pink spots. From I. janthina, it differs in its branched thicker stem, longer flower stalks, spurless lower sepal and elongate-fusiform capsules.
Q: The species appears to be closely associated with continuously wet, seepage-fed rock surfaces. What is it about this very specific microhabitat that makes it suitable for the Kitulgala Balsam?
A: The plants grow in small rock depressions and crevices where water continuously seeps across the surface. These places remain moist and humid and accumulate small amounts of moss and organic matter, creating suitable conditions for establishment. The continuous water supply appears to be especially important.
Q: How important are these small, specialised microhabitats to Sri Lanka’s overall plant biodiversity?
A: They are extremely important because many endemic plants are restricted to very specific habitats. Even a small seepage zone, rocky outcrop or stream margin can support specialised species found nowhere else. Losing a small habitat can therefore mean losing an entire population.
Q: The species is currently known from only one locality. How concerned are you about having an entire known population concentrated in such a small area?
A: It is a major concern. Although the population contains more than a thousand individuals, the entire known population occurs in one small area. A single disturbance, such as habitat modification, trampling or changes to water flow, could affect a large part of the population.
Q: Could increased tourism or future development around Manna Kathi Ella unintentionally put additional pressure on this habitat?
A: Yes. Trampling, trail widening, vegetation clearing, waste disposal and changes to drainage could all affect the habitat. However, with proper management and awareness, tourism can also help support conservation rather than becoming a threat
Q: What are the next steps in research on Impatiens yakandawalarum?
A: We plan to survey surrounding areas for additional populations and continue monitoring the known population. Molecular studies are also underway to better understand its relationship with other Sri Lankan Impatiens. Further work on its ecology, reproduction and propagation will also support future conservation planning.
Q: Finally, what does discovering a new plant species in 2026 tell us about how much there is still left to discover in Sri Lanka’s natural heritage?
A: It shows that Sri Lanka still has much more to discover, even in relatively well-studied and frequently visited areas. In fact, we have already submitted another two manuscripts describing two additional new Impatiens species from Sri Lanka. This highlights the importance of continued field exploration, taxonomy and herbarium research. We cannot effectively conserve species and habitats unless we first know what exists.
Research source:
Gopallawa, B., Hapuarachchi, S. I., Jayathissa, C., Gunarathna, S. S., & Karunarathna, P. P. (2026). A New Ecalcarate Species of Impatiens (Balsaminaceae) from the Lowland Wet Zone of Sri Lanka. Ceylon Journal of Science, 55(4), 1424-1433. DOI: 10.4038/cjs.v55i4.10118
Images courtesy of Bhathiya Gopallawa – Research Assistant at the Postgraduate Institute of Science (PGIS), University of Peradeniya.
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