Rock outcrops are geological formations that harbor a highly specialized biota adapted to harsh environmental conditions that differ from their surrounding landscapes. They are globally distributed, especially in old, highly weathered landscapes, and can function as habitat islands containing high levels of endemism and distinct evolutionary lineages. Despite their ecoevolutionary importance, rock outcrops remain largely overlooked in global conservation policy, ecosystem typologies, and biodiversity monitoring frameworks. Extractive activities directly remove the geological substrate that underpins these habitats, and climate change intensifies drought, heatwaves, and hydrological instability. Rising global demand for energy-transition metals required for decarbonization is expected to further accelerate these pressures, particularly in biodiverse regions of the Global South where governance is weaker. Given that rock outcrop ecosystems are ecologically and evolutionarily significant, we devised a policy-relevant conservation roadmap structured around prevention, mitigation, restoration, and governance issues. Priority actions include recognizing rock outcrops as unique ecosystems in global classifications and ecosystem typologies, integrating them into biodiversity monitoring frameworks, and improving the identification of key biodiversity areas and the International Union for Conservation of Nature (IUCN) Red List of Ecosystems assessments. We call for stronger environmental impact assessments, cumulative-impact evaluations for mining and quarrying projects, and the designation of mining and quarrying exclusion sites of high irreplaceability. Coordinated international policy, improved ecological data, and meaningful engagement with local and Indigenous communities are essential to safeguard these ancient ecosystems before further, irreversible losses occur.

Plant strategies to cope with drought often involve a conservative resource-use to prioritise survival over growth. However, important trade-offs are associated with plant stress tolerance. A good example of that are vascular desiccation-tolerant plants, which can tolerate almost complete loss of water in their vegetative tissues but are also expected to show a high resource acquisition upon rehydration, using the opportunity of water availability to grow. In this study, we evaluated desiccation-tolerant plants resource-use strategies and compared their responses with their ability to tolerate desiccation. For that, we subjected four desiccation-tolerant plant species to a desiccation-rehydration cycle and measured different traits associated with resource-use, describing growth restriction (i.e., environmental stress) and biomass loss (i.e., disturbance) as proxies for species ability to tolerate desiccation. We found that traits cannot individually describe species ability to tolerate desiccation, as drought leads desiccation-tolerant plants to environmental stress when mild and disturbance when it exceeds their capacity to tolerate desiccation. Therefore, desiccation-tolerant plants responses to drought might not be dependent on only one trait but on the combination of an array of traits and their inherent trade-offs. We discuss and propose an adapted framework on alternative functional designs to better explore different trait combinations in desiccation-tolerant plants, which we believe could play a key role in improving our mechanistic understanding of drought tolerance.

Alarming trend in biodiversity decline has been observed due to anthropogenic drivers, reinforcing the need to identify priority species for conservation. We discuss the prioritisation of species with small distribution sizes for conservation through two often-neglected perspectives: exposure to human-driven threats and importance to biodiversity. To evaluate species exposure, we estimated the amount of human pressure within their distribution ranges. To estimate species distinctive contributions to ecosystem functions and services, we calculated decreases in phylogenetic diversity after sequential species exclusion. We found that species with smaller distribution ranges are not the most exposed to human-driven threats, as phylogenetic diversity is not always affected by the loss of these species when compared to species with broader distribution ranges. We propose conservation strategies to cope better with species vulnerability and to identify species with higher conservation needs. Species undergoing high exposure to human-driven threats would benefit from conservation initiatives distinguishing the causes of smaller range size. Ecosystem management could focus on species whose distribution is mostly limited by abiotic suitability, while species management could be more adequate for species whose distribution is mostly limited by accessibility. We also discuss the use of a response–effect framework to improve our capacity to identify species more negatively impacted by human-driven threats and with more distinctive effects on ecosystem processes. Species with smaller distribution ranges should be prioritised for conservation when a negative correlation between species ability to cope with environmental change and the distinctiveness of their effects on ecosystem processes is found.

Climate change affects biodiversity faster than conservation assessments can be conducted. This issue calls for approaches that support decisions on conservation prioritization, such as species phylogenetic relationships or diversity and endemism metrics. However, these traditional approaches often neglect some important aspects, limiting their effectiveness. We used desiccation-tolerant vascular plants (DT plants) to investigate the effectiveness of such approaches to prioritize species and areas for conservation. We used climate data and modeled the distribution of all DT plants recognized to date to evaluate if species phylogenetic relationships can depict similarities in species sensitivity and exposure to climate change, and to evaluate if centers of diversity and endemism for DT plants can indicate regions prone to climate change. We found that the species phylogenetic relationships weakly explains species sensitivity to climate change, although it can, to some extent, describe trends in species exposure to climate change. We also found that centers of diversity and endemism for DT plants are not necessarily the most prone ones to climate change. We suggest a limited effectiveness of phylogenetic relationships and of diversity and endemism metrics for conservation prioritization, once these approaches might overlook vulnerable species and regions exposed to climate change. We discuss that a better understanding of the mechanisms of diversity would help to identify situations in which closely related species show lower ecological differences than distantly related species, when phylogenetic relationships is a more relevant approach in a conservation context. We also suggest that more efficient conservation strategies in centers of diversity and endemism of DT plants should focus on species sensitivity and adaptive capacity to climate change, rather than the magnitude of climate change. ### Competing Interest Statement The authors have declared no competing interest. Deutscher Akademischer Austauschdienst, 57440921 Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, E-26/200.401/2019 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, 88887.569558/2020-00

The anthropogenic drivers of biodiversity loss are causing a global decline in biodiversity, yet some species remain overlooked in conservation efforts. In this study, we address the gaps between the current discussions and pressing issues on these species’ conservation. We focused on West Africa and used desiccation-tolerant vascular plants to conduct a systematic review of conservation discussions and a study case to assess their protection and exposure to quarrying and climate change. Our systematic review revealed, for the first time, that these plants are largely neglected in conservation discussions. Most species lack formal evaluations, and only four studies mentioned conservation, although without providing enough evidence to justify it. In our case study, we found biased protection among the species, with varying effectiveness of the protection areas against different anthropogenic threats. The two most exposed species were not present in protected areas, which were more effective at mitigating quarrying impacts than climate change. We highlight the need for conservation-explicit assessments and a mechanistic understanding of species’ conservation needs, such as quantitatively evaluating species vulnerability to threats, to support efficient conservation strategies. We call for conservation initiatives with specific objectives to include overlooked species in protected areas and adjust the conservation objectives to address specific threats.

Effective forest conservation relies on active community participation; however, local communities in Ghana are often excluded from policy development. This study explored community perspectives on forest conservation by identifying practices that local inhabitants believed could help preserve the forests in two wildlife-protected areas within the forest-savannah transition zone of Ghana: Boabeng-Fiema Monkey Sanctuary (BFMS) and Kogyae Strict Nature Reserve (KSNR). A cross-sectional survey involving 300 respondents was conducted using semi-structured questionnaires to gather insights into locally suggested conservation practices. A Multinomial Logistic Regression (MLR) model was employed to assess whether the socio-demographic variables such as age, sex, educational level, occupation and residential status influenced these perspectives. Wildfire prevention was the most emphasised conservation strategy in BFMS (38.6%), while respondents in KSNR (37.2%) emphasised increased staffing for effective forest monitoring. Socio-demographic variables had no statistically significant influence (p > 0.05) on respondents’ perspectives. The findings highlight the importance of integrating local knowledge and community-driven conservation approaches for effective forest management. Strengthening participatory strategies can enhance conservation outcomes and contribute to the achievement of Sustainable Development Goals 13 (Climate Action) and 15 (Life on Land), which focus on biodiversity conservation and ecosystem resilience.

Protected areas are the mainstay of biodiversity, serving as important habitats for endangered and threatened species. However, increasing anthropogenic activities threaten their long-term sustainability. This study assessed the conservation status of Boabeng-Fiema Monkey Sanctuary (BFMS) and Kogyae Strict Nature Reserve (KSNR), two wildlife-protected areas in the transition zone of Ghana, currently facing human-induced disturbances. The Genetic Heat Index (GHI) and Red List Index (RLI) were used to evaluate the conservation status of the sites. The assessment revealed significant conservation values for BFMS and KSNR, with GHI values of 134.24 and 105.41, respectively. BFMS recorded an RLI value of 0.21, while KSNR had a negative RLI value of − 1.55, primarily due to the prevalence of Pterocarpus erinaceus , an endangered tree species on the IUCN Red List. These results reiterate that protected areas are biodiversity hotspots and resilient ecosystems. Immediate action is needed to protect biodiversity and prevent further extinction of valuable tree species. Preserving BFMS and KSNR not only defends against biodiversity loss but also contributes meaningfully to the achievement of Sustainable Development Goals 11 (Sustainable Cities and Communities), 13 (Climate Action) and 15 (Life On Land), particularly in the face of global climate change.

Background and aims Climate change affects global biodiversity, and species such as desiccation-tolerant vascular plants (DT plants) remain largely neglected in conservation objectives and individual initiatives, West Africa is no exception. Our study aims to assess the impact of climate change on DT plant distribution and diversity in West Africa. Material and methods In this study, we use all DT plants described to West Africa and their occurrences, and employ species distribution models to depict changes in their distribution and diversity when comparing present and future climate change conditions. Key results We identified a consistent contraction of DT plants’ distribution ranges and a significant shrinkage of their centres of diversity and endemism. Conclusion It is imperative that future research and on-the-ground conservation efforts should focus on species-specific conservation needs, including closely monitoring DT species with small distribution ranges and assessing the conservation requirements of DT species with broad distribution ranges. It should also be stressed the urgency of integrating climate projections into the conservation planning of DT plants worldwide to ensure that effective conservation strategies include the expansion of protected areas specifically designed to improve stewardship of conserved DT plants.

Climate change is recognized as one of the main drivers of plant species extinction, including palms. The objective of the present study is to assess the potential distribution and vulnerability of four multipurpose wild palm species, namely Borassus akeassii, Elaeis guineensis, Phoenix reclinata and Raphia sudanica, to climate change in Burkina Faso. Occurrence data (445) of these species were collected from fieldwork, literature and GBIF. The environmental layers consisting of bioclimatic data, soil variables, topographic position index and drainage density were obtained from different sources and linked to the occurrence data through the Maximum entropy algorithm. The models were validated and binarized. The presence maps were integrated into the CENFA framework to assess the vulnerability of each palm species. The results showed that precipitations and topographic position index were determinant variables for the four palm species distribution in western Burkina Faso. The potential distribution area of the four palm species in Burkina Faso varied between 10 and 15% of the surface area of the country. Climate change may induce a range expansion (up to 28.51%) or contraction (up to-16%) depending on the palm species, the global circulation models and climate scenarios. The climate change-caused vulnerability assessment indicated that Borassus akeassii is less vulnerable than Elaeis guineensis, Phoenix reclinata and Raphia sudanica in Western Burkina Faso. This study highlights the importance of considering the sensibility of palm species in assessing their vulnerability to global climate change. Moreover, the results call for more conservation actions on Elaeis guineensis, Phoenix reclinata and Raphia sudanica in Burkina Faso.

Islands are fundamental model systems in ecology, biogeography, and evolutionary biology. However, terrestrial islands, unlike their aquatic counterparts, have received comparatively less attention. Among these land islands, inselbergs (i.e. isolated rock outcrops with diverse lithologies and a modest topographical prominence) stand out as iconic examples distributed worldwide across global biomes. Due to their durable lithology, inselbergs change slowly, persisting for tens of millions of years. In this review, we propose a biological definition for inselbergs that captures three fundamental characteristics of inselbergs from the perspective of biota. These are old age, isolation and the presence of unique microhabitats that are rare or absent in the surrounding matrix, fostering distinct communities often with unique and endemic biota. We synthesise the state of the art and formulate a set of testable hypotheses to deepen our understanding of the origins and maintenance of diversity on inselbergs, which are increasingly exposed to anthropogenic threats. By offering different habitats compared to the surrounding habitat matrix (e.g. moist microhabitats in dryland landscapes and xeric environments in humid tropical landscapes), inselbergs may allow specific lineages to thrive beyond their typical geographical limits. Particularly in drylands and degraded landscapes, inselbergs may not just provide different habitats but also act as ecological refuges or evolutionary refugia by providing a wider range of potential microhabitats than the surrounding matrix, enhancing resilience and promoting regional biodiversity. The central role of the matrix ensures that the ecological and evolutionary dynamics of inselbergs differ from those of true islands such as oceanic islands. Given that inselberg biota coexist within a terrestrial matrix, interactions between inselberg and matrix populations impact each other significantly. Over evolutionary timescales, matrix species may contract to inselberg refugia, preserving lineages while cycles of isolation and reconnection may drive speciation via a species pump. Although inselberg biodiversity has been studied predominantly from an island biogeography perspective, we argue that depending on the spatial scale, habitat specificity and mobility of the organisms considered, a range of different theories and paradigms can help explain the biogeography and local distribution patterns of different taxonomic and functional groups of inselberg species.

Inselbergs, composed of granite or gneissic rocks, rise abruptly from the landscape, forming island habitats.In southeast Brazil, these dome-shaped lowland Inselbergs, located in the Atlantic Forest Domain, are known as sugar loaves, and the area encompassing these outcrops is called "Sugarloaf Land" (SL).Due to adverse conditions such as lack of soil and water and high UV radiation, plant communities in Inselbergs exhibit specific adaptations, forming distinct habitats such as vegetation mats, mainly from monocot families.Notably, Velloziaceae, well adapted to drought, form mats in these Inselbergs but do not occur in the surrounding matrix.This study provides detailed maps of the distribution of Vellozia species in the SL region, highlighting endemic and widely distributed species.Vellozia species in these outcrops present taxonomic challenges, so we examined the relationship between geographic distribution and morphological plasticity.We identified seven species: Vellozia albiflora, V. bahiana, V. candida, V. inselbergae, V. plicata, V. pulchra and V. variegata.Despite having similar attributes, such as adventitious roots and desiccation tolerance, Vellozia species show different distribution patterns, with widely distributed species exhibiting greater morphological plasticity.By comparing distribution patterns and environmental conditions, researchers can better understand the evolutionary relationships and adaptive responses of these plants.

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems.

Native multi-purpose tree species in West Africa, Cola nitida and Garcinia kola have the potential to advance agroforestry practices in the sub-region. There is limited information on the ecology of both species which are currently characterised by low yield (fruit). This study investigated the influences of vegetation type on the population structure and floral association of both species in Nigeria. Data were collected using a purposive sampling design. Dendrometric variables of all the subject trees were measured, and all plant species associated with the subject tree species were enumerated across their places of natural occurrence. A 3-parameter Weibull Distribution Function was used to describe both species diameter and height structures. Data were analysed using descriptive and inferential statistics. A total of 84 and 71 plant species were found accompanying G. kola and C. nitida, respectively, in both zones. The height and stem diameter distribution of the two species showed a bell-shape population structure, suggesting an unstable demographic pattern. The diameter distribution is skewed to the right, indicating the predominance of adult individuals. The height-diameter relationships show a monotonic increment. Both species coexist freely with other species and can be used in agroforestry practices.

The safeguarding and sustainable management of natural resources, particularly plant resources, requires the implementation of conservation strategies. The study of plant communities is an essential tool for monitoring the development of plant formations. The aim of this study was to identify the plant communities on inselbergs of Burkina Faso in West Africa, to provide a database to supporting the sustainable management of the plant resources withing these fragile ecosystems. Stratified and random sampling was carried out on selected inselbergs in different parts of Burkina Faso along a climatic gradient. In the different phytogeographical sectors, inselbergs consist of granite or sandstone. Plant surveys were conducted using 900 m2 plots for the woody stratum and 100 m2 plots for the herbaceous stratum. An exhaustive list of plant species was compiled and an abundance-dominance coefficient for each species was determined. A DCA, through PCord.6, was used to obtain preliminary groups. Indicator species were determined by a Monte Carlo test with p < 0.05 and calculation of the fidelity index (Phi). Diversity indices through the Shannon index and equitability of Pielou were calculated using Pcord.6 to compare plant communities. A total of 12 plant communities were identified for the inselbergs of Burkina Faso, including 9 communities for savannah and 3 communities for monocotyledonous-mats and ephemeral flush vegetation. The main ecological factors governing the distribution of these inselberg plant communities were found to be were found to be climate, soil depth, soil moisture and altitude. In savannah plant communities, the Terminalia laxiflora and Tephrosia nana communities (unit 6) had the highest number (13) of diagnostic species and the highest fidelity (Phi = 0.97) was for Cleome viscosa species in the Acacia tortilis and Aristida kerstingii communities (unit 1). Diagnostic species numbers vary from 6 to 4 in monocotyledonous-mats and ephemeral flush vegetation and the Dopatrium longidens (Phi = 0.76) and Cyperus podocarpus (Phi = 0.75) have the highest fidelity to unit 3. The Shannon diversity index of deep soil plant communities was highest and significantly different from that of the other savannah communities. Concerning the Piélou equitability index, high values were found in all plant groups, reflecting the absence of species dominance and a balance of the different plant groups.Floristically, Afrotrilepis pilosa infestation of inselbergs is common in West Africa. In Burkina Faso, in addition to Afrotrilepis pilosa, 10 other plant species are found specifically on inselbergs. Given the fragility of the ecosystems in which they live, these inselberg species should be protected.

Tropical forests play a significant role in climate change by sequestering atmospheric carbon dioxide. However, deforestation and forest degradation adversely affect these forests’ carbon stocks. Reports indicate that anthropogenic activities have led to forest degradation and deforestation in Boabeng Fiema Monkey Sanctuary (BFMS) and Kogyae Strict Nature Reserve (KSNR). This study assessed the effects of these activities on the carbon stocks of BFMS and KSNR. Using satellite imagery, field measurements and allometric models, carbon stocks of the study area were assessed from 1992 to 2023. The assessment revealed significant losses attributed to anthropogenic activities, such as hunting, farming and charcoal burning. BFMS experienced a total loss of 40,236 Mg C, while KSNR lost 272,109 Mg C. The closed forests had the highest carbon stock amongst the different vegetation types, with soil representing the most significant carbon pool in the protected areas, revealing the influence of vegetation structure on carbon sequestration and the need for soil conservation. The substantial carbon sequestration potential observed in the different vegetation types of the study area indicates that the Forest-Savannah Transition Zone is a prospective area for climate change mitigation aligning with the Sustainable Development Goals (Goals 13 and 15) and the National Climate Change Policy of Ghana. These findings provide valuable insights for carbon trading and biodiversity conservation, emphasizing the potential of nature-based solutions in addressing global climate challenges.

Background: Water deficit is one of the main drivers of plant mortality and is projected to be more critical owing to climate change. Because desiccation-tolerant vascular plants (DT plants) can cope with water deficit, the paradigm emerges of their strong association with and restricted occurrence to locations characterised by water deficit conditions. However, this paradigm is not supported by earlier studies, hampering our understanding of the species - environment relationships and the vulnerability of DT plants to climate change. Aims: We tested this paradigm and provide an evaluation of the vulnerability of DT plants to climate change. Methods: We estimated the diversity and distribution of DT plants along water deficit gradients and assessed species vulnerability to climate change from a climatic perspective and over broad phylogenetic and macroecological scales. Results: The diversity and distribution of DT plants were neither associated with, nor restricted to, locations characterised by water deficits. Species with narrow niche breadth and poikilochlorophylly might be the most vulnerable to climate change. Conclusions: Our findings suggest that the desiccation events DT plants undergo are promoted by topo-edaphic conditions rather than by climate. We suggest that ecologically restricted species and those with a poikilochlorophyllous strategy should be prioritised for conservation.

Vascular epiphytes are a characteristic life form in many tropical regions and often occur growing on bare rocks. South America has the highest diversity. Here, we describe a neglected life form: hyperepilithics adapted and restricted to growing on vertical (inclination above 70°) and bare rock walls without having roots intruding the substrate. Hyperepilithics are in particular present on Brazilian inselbergs and dominated by highly specialized Bromeliaceae, mainly of the genera Stigmatodon , Tillandsia and Alcantarea , whereas Orchidaceae surprisingly has a low representation. An overview of this habitat, the life form hyperepilithics and a comparison with similar paleotropical habitats (mainly inselbergs in Western/Eastern Africa and India) are provided. Attention is drawn to hyperepilithics as a most promising and not yet exploited source for a sustainable urban ‘vertical gardening’, for example in tropical megacities.

Faced with the loss of biodiversity, particularly plant diversity, due to anthropogenic pressure, particular ecosystems such as inselbergs can constitute refuge areas. The objective of this study is to determine the conservation potential of plant biodiversity on inselbergs in Burkina Faso. A comparative study was carried out between inselberg’s vegetation and the surrounding plains vegetation. In each of these vegetation types, stratified and random sampling was adopted and data were collected in plots of 900 m² for the woody stratum and 100 m² for the herbaceous stratum. The specific diversity was evaluated through the effective numbers of Hill of order Q = 0; 1; 2. The Hill index does not vary between inselbergs and plains and thus reflects a strong similarity in floristic diversity between the two ecosystems. Sorensen’s similarity coefficient also shows a similarity in terms of floristic composition between inselbergs and surrounding plains. In inselbergs, relict species that have disappeared from the surrounding plains of some phytogeographic sectors occur. The flora of inselbergs is also characterised by indicative species of anthropized ecosystem absence. However, these species are present on the surrounding plains. Indeed, the flora of inselbergs is characterised by 11 endemic species. Inselberg’s vegetation is characterised by unique plant communities such as rock pools and Afrotrilepis pilosa mats. The exploitation and mortality rates of woody plants are significantly higher on the surrounding plains than on the inselbergs. The flora and vegetation of inselbergs show the absence of indicator species of disturbed ecosystems. They present endemic and relict species and stable woody stands. Due to the steep slope, lack of suitable soil for agriculture and sacred status of someones, the inselbergs constitute a refuge for plant species and thus contribute to the conservation of biodiversity like the protected areas.

BACKGROUND AND AIMS:Desiccation-tolerant vascular plants (DT plants) are able to tolerate the desiccation of their vegetative tissues; as a result, two untested paradigms can be found in the literature, despite contradictions to theoretical premises and empirical findings. First, it is widely accepted that DT plants form a convergent group of specialist plants to water deficit conditions. A derived paradigm is that DT plants are placed at the extreme end of stress tolerance. Here, we tested the hypotheses that DT plants (1) are in fact convergent specialists for water deficit conditions and (2) exhibit ecological strategies related to stress tolerance, conservative resource-use and survival.METHODS:We used biogeographical and functional-traits approaches to address the mentioned paradigms and assess the species' ecological strategies. For this, 27 DT plants were used and compared to 27 phylogenetically related desiccation-sensitive vascular plants (DS plants).KEY RESULTS:We could not confirm either of the two hypotheses. We found that despite converging in desiccation tolerance, DT plants differ in relation to the conditions in which they occur and the ecological strategies they use to deal with water deficit. We found that some DT plants exhibit advantageous responses for higher growth and resource acquisition, which are suitable responses to cope with more productive conditions or with higher disturbance. We discuss that the ability to tolerate desiccation could compensate for a drought vulnerability promoted by higher investment in growth and bring advantages to deal with quick and pronounced variation of water, rather than to drought solely.CONCLUSIONS:DT plants are not only selected by drought as an environmental constraint. The alternative functional designs could promote the diversity of ecological strategies, which preclude their convergence to the same resources and conditions. Thus, DT plants are a heterogeneous group of plants in how they deal with drought, despite their desiccation tolerance ability.

A rupicolous, resurrection, inselberg specialist plant is newly described and illustrated. Linderniella porembskii Andriamiar. & Rabarim. (Linderniaceae) is restricted to central Malagasy granitic inselbergs in the Amoron'i Mania Region. It differs from the other Malagasy species of the genus by its habit with dense and richly branched stems, decumbent to erect, and by being glabrous to glabrescent and having obovoid-acuminate capsule. A detailed description of the species is provided, accompanied by illustrations and an identification key to the Malagasy species of the genus. The new species is assessed as "Endangered" using to IUCN Red List Categories.