Hubbry Logo
AdeniumAdeniumMain
Open search
Adenium
Community hub
Adenium
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Adenium
Adenium
Adenium
View on Wikipedia
from Wikipedia

Adenium
Adenium obesum
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Gentianales
Family: Apocynaceae
Subfamily: Apocynoideae
Tribe: Nerieae
Genus: Adenium
Roem. & Schult.[1]
Synonyms[2]
  • Adenum G.Don
  • Idaneum Kuntze & Post
Seedlings

Adenium is a genus of flowering plants in the family Apocynaceae first described as a genus in 1819. It is native to Africa and the Arabian Peninsula.[3]

Cultivation and uses

[edit]
Adenium in Thailand

Adenium obesum is grown as a houseplant in temperate and tropical regions. Numerous hybrids have been developed. Adeniums are appreciated for their colorful flowers and unusual thick caudices. They can be grown for many years in a pot and are commonly used for bonsai.

One of the paired, follicular fruit of an Adenium species, dehiscing to release seeds equipped with a double pappus (i.e. tuft of hairs at each end) for wind-dispersal

Because seed-grown plants are not genetically identical to the mother plant, desirable varieties are commonly propagated by grafting. Genetically identical plants can also be propagated by cutting. Cutting-grown plants do not tend to develop a desirable thick caudex as quickly as seed-grown plants.

The sap of Adenium boehmianum, A. multiflorum, and A. obesum contains toxic cardiac glycosides and is used as arrow poison throughout Africa for hunting large game.[4]

Classification

[edit]

The genus Adenium has been held to contain as many as twelve species. These are considered by other authors to be subspecies or varieties. A late-20th-century classification by Plazier recognizes five species.[5]

Species[3]
  1. Adenium arabicum Balf.f. = Adenium obesum
  2. Adenium boehmianum Schinz - (Namibia, Angola)
  3. Adenium multiflorum Klotzsch. (Southern Africa, from Zambia south)
  4. Adenium obesum (Forssk.) Roem. & Schult. - widespread from Senegal to Somalia, and also Arabian Peninsula
  5. Adenium oleifolium Stapf - South Africa, Botswana, Namibia
  6. Adenium swazicum Stapf (Eastern South Africa)[5][6]
Desert rose
Formerly placed here

Common names

[edit]

Adenium obesum is also known as the desert rose. In the Philippines, due to its resemblance to the related genus Plumeria, and the fact that it was introduced to the Philippines from Bangkok, Thailand, the plant is also called as Bangkok kalachuchi.[citation needed]

Due to its resemblance to a miniature frangipani tree and its popularity in bonsai, it is also sometimes known as Japanese frangipani.

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Adenium

View on Grokipedia
from Grokipedia
Adenium is a of flowering in the family , consisting of six accepted species of semisucculent shrubs and small trees native to the arid and semi-arid regions of tropical and as well as the . These are characterized by their thick, fleshy stems that often swell at the base to form a for water storage, alternate leaves clustered at branch tips, and showy, tubular flowers in shades of pink, red, white, or purple that bloom primarily during warmer months. The genus produces a milky and features follicles as , with seeds equipped with hair tufts for wind dispersal, adaptations well-suited to their desert and dry habitats. The most widely recognized species is Adenium obesum, commonly known as the desert rose, which is prized for its ornamental value in cultivation worldwide due to its striking blooms and sculptural form resembling a tree. Native to a broad range from West Tropical to the and , A. obesum can reach heights of up to 6 meters in the wild but is typically grown as a compact potted , requiring well-drained soil and full sun to thrive. Other accepted species include Adenium boehmianum, found in southern and ; Adenium dhofarense, endemic to southern ; Adenium multiflorum, distributed across southern tropical and southern ; Adenium oleifolium, native to southern ; and Adenium swazicum, occurring in southern and . These species vary in flower color, shape, and caudex development, but all share the genus's resilience to and low water needs. Beyond their aesthetic appeal, Adenium species hold cultural and practical significance, though they are notably toxic due to cardiac glycosides in their sap, which can cause severe poisoning if ingested by humans or animals. In some African traditions, extracts from the plants have been used medicinally or as arrow poisons, highlighting their potent alkaloids, while in modern horticulture, they are hybridized for enhanced flower production and are popular in arid landscaping or as indoor specimens in temperate climates. Taxonomic debates persist regarding species boundaries, with some varieties potentially warranting elevation to full species status based on morphological and genetic differences. Overall, Adenium exemplifies the beauty and danger of desert-adapted flora, bridging wild survival strategies with global ornamental cultivation.

Taxonomy and Etymology

Classification

Adenium belongs to the Kingdom Plantae, Phylum Tracheophyta, Class Magnoliopsida, Order Gentianales, Family Apocynaceae, Subfamily Apocynoideae, and Tribe Nerieae. Within the Apocynaceae family, Adenium shares its tribe Nerieae with genera such as Nerium, and species in both genera produce cardiac glycosides that contribute to their toxicity, affecting cardiac function in animals and humans. The classification of species within Adenium remains debated, with some authorities recognizing up to 12 taxa while modern treatments such as accept six species: A. boehmianum, A. dhofarense, A. multiflorum, A. obesum, A. oleifolium, and A. swazicum. Subspecies are also recognized in certain classifications, such as A. obesum subsp. socotranum, which is endemic to the island of , though often treated as a synonym of A. obesum in contemporary .

History and Etymology

The genus Adenium traces its botanical origins to the mid-18th century, when Swedish naturalist Peter Forsskål first described the type species as Nerium obesum in 1775, based on specimens collected from the region around in during the Danish expedition to Arabia. This initial description highlighted the plant's distinctive swollen base, with the specific epithet obesum derived from Latin, meaning "fat" or "stout," in reference to its thickened that stores water in arid environments. The genus name Adenium itself is a Latinization of the local vernacular "Öddajn" or "Aden," directly alluding to the Yemeni port city near the initial collection site. In 1819, German botanists Johann Jacob Roemer and Josef August Schultes formally established the genus Adenium in their work Systema Vegetabilium, transferring Nerium obesum to it as the type species and distinguishing it from related genera like Nerium based on floral and vegetative characteristics. This classification marked the recognition of Adenium as a distinct group within the Apocynaceae family, emphasizing its succulent habit and adaptation to dry tropical regions. During the 19th century, European explorations in Africa and the Arabian Peninsula expanded knowledge of the genus through key collections by botanists such as Otto Stapf and Isaac Bayley Balfour, who documented variations leading to new species descriptions. For instance, Balfour described Adenium arabicum in 1888 from specimens gathered on the Arabian Peninsula, noting its robust, baobab-like trunk and distinguishing it from the type species based on habitat and morphology. These efforts, often tied to broader surveys like the Flora of Tropical East Africa, revealed the genus's wide distribution across arid zones and prompted initial taxonomic splits. The 20th century brought significant revisions to Adenium's taxonomy, culminating in H.W.G. Plazier's 1980 monograph, which consolidated earlier descriptions into a framework of five distinct species—A. boehmianum, A. multiflorum, A. obesum, A. oleifolium, and A. swazicum—based on morphological, geographical, and distributional evidence from herbarium specimens and field observations. This classification reduced the number of previously recognized taxa by synonymizing many variants under these core species, providing a stable foundation for subsequent studies while acknowledging ongoing variability in peripheral populations.

Species and Varieties

The genus Adenium comprises a small number of , with six accepted according to recent taxonomic assessments such as , though horticultural and some botanical treatments recognize five primary by treating certain taxa as distinct despite synonymy debates. Recent genetic analyses suggest potential separation of some synonyms like A. arabicum and East African variants (e.g., A. somalense) based on levels and phylogeny, though these are maintained as synonyms in standard checklists. These exhibit infrageneric variation in development, flower coloration ranging from pink and red to white (with rare yellow tones in some populations), and leaf morphology, such as narrow lanceolate leaves in southern African taxa versus broader elliptic forms in Arabian ones. Natural populations maintain species purity, but in cultivation, interspecific hybridization is widespread for ornamental traits like enhanced flower size and color intensity. Adenium boehmianum Schinz is endemic to eastern and southern , ranging from southern through to northwestern , forming a by or small tree habit with modestly succulent stems and a less pronounced compared to Arabian relatives. It produces tubular flowers in shades of pink to white, often with a deep purple throat, and broader grayish-green leaves. Adenium dhofarense Rzepecky, described in 2015, is endemic to southern , growing as a semisucculent in coastal dry with large leathery leaves, gray bark, and small pink flowers; it is distinguished by morphological and genetic traits from A. obesum. Adenium multiflorum Klotzsch occurs in , characterized by a multi-stemmed shrubby growth and dense clusters of pink flowers borne on the stems. The species features elliptic leaves and a moderate , distinguishing it from more upright congeners. Adenium obesum (Forssk.) Roem. & Schult. has the widest distribution, from western tropical across the to , displaying high variability in form from low shrubs to small trees with a swollen . Flowers are predominantly red to pink, with some populations showing white variants; it encompasses forms previously classified as subsp. socotranum (Vierh.) Lavranos from , noted for its massive, bottle-shaped trunk, and synonyms like A. arabicum Balf.f. and var. somalense . Within this species, varieties such as var. obesum (widespread mainland form) contrast with regional variants; notable historical synonyms include Adenium coetaneum Stapf. Adenium oleifolium Stapf is native to , particularly and , forming low shrubs with olive-like leaves, slender stems, and a weakly developed ; it produces pale pink flowers. Adenium swazicum Stapf is restricted to southern and , exhibiting an upright, sparsely branched habit with a relatively slender and narrow leaves. Its flowers are white to pale pink, often with a deeper-colored throat, setting it apart from the more vividly hued A. multiflorum.

Description

Morphology

Adenium species are succulent shrubs or small trees, typically growing to 1–5 meters in height, with a distinctive swollen at the base that serves as a organ and can reach diameters of up to 1 meter in mature specimens. This pachycaul habit gives the a sculptural appearance, often with a fleshy supporting the enlarged basal stem; root systems vary across species, with some featuring rhizomatous or carrot-like tubers. The stems and branches emerge from the , featuring thick, gray to gray-green bark that is smooth and lenticellate; they are sparsely branched, erect or spreading, and become glabrescent except at the pubescent apices. In response to seasonal dryness, the branches often become , shedding leaves to conserve . Leaves are simple, arranged alternately or in clusters at the tips of branches, with an obovate to linear shape, measuring 5–15 cm in length and 0.5–4 cm in width; they are leathery, glabrous, and dull green, with a prominent midrib and indistinct lateral veins. Petioles are short, up to 5 mm long, and the leaves cluster densely at branch ends, contributing to the 's sparse, open crown. Flowers are bisexual and showy, forming in terminal cymes with peduncles 1–2.5 cm long; each flower has a salver-shaped corolla that is tubular, 3–6 cm long overall, with a swollen base and five obliquely obovate lobes spreading outward. The corolla lobes, 1–3 cm long, exhibit colors ranging from pink and red to white or yellow, often with paler bases and veins, and are pollinated primarily by such as butterflies and bees. Fruits develop as paired, distinct follicles that are long and slender, straight or slightly curved, 10–20 cm in length and 0.8–1.5 cm wide, with an attenuate apex and pale brown color at maturity. Each follicle contains numerous oblong seeds, 10–14 mm long, equipped with a 2–3.5 cm long white of hairs at both ends that aids in wind dispersal. Adenium plants exude a milky latex sap from wounds in the stems, bark, and leaves, which contains cardiac glycosides responsible for the genus's toxicity to humans and animals. This sticky, white to clear sap can cause skin irritation upon contact.

Reproduction

Adenium species primarily reproduce sexually through seeds, with no documented asexual reproduction occurring in the wild, although vegetative propagation is common in cultivation. Flowering phenology is closely tied to environmental cues in their arid native habitats, where blooming typically initiates after seasonal rains, producing clusters of tubular flowers that open in the morning and close at night. Individual flowers last 5–7 days, with the overall blooming period spanning 30–35 days per inflorescence, though plants may exhibit prolonged or multiple flowering cycles under favorable conditions. Pollination in Adenium is predominantly entomophilous, facilitated by such as and moths equipped with long proboscises that access through slits in the anther cone, transferring to the stigma. Many accessions display , with approximately 25% of ovules aborting post-self-pollination due to genetic barriers that promote ; cross-pollination yields higher fruit set, though rare self-fertilization can occur. remains highly fertile for 3–4 days after , enabling effective manual or natural transfer. Following successful , paired follicles develop over approximately 90 days, maturing to 15–25 cm in length before splitting longitudinally to release . Each follicle contains 28–118 on average, equipped with a —a tuft of silky hairs at one end—that facilitates wind dispersal in open habitats, allowing self-seeding in suitable microsites. In natural settings, production supports persistence, though rates vary with availability and genetic compatibility. Seeds of exhibit high initial viability, with freshly harvested ones achieving up to 96% under optimal conditions. Viability persists for several months if stored dry, but requires exposure to and consistent , typically occurring within 7–14 days in warm, wet environments that mimic post-rainfall conditions; seedlings show rapid elongation in response to these cues.

Distribution and

Geographic Range

The genus Adenium is native to tropical and subtropical and the , with distributions spanning from in eastward to and southward to , as well as , , , and the island of . Adenium obesum, the most widespread species, occurs across semi-arid regions of the from and to and , extending south to , , and , and across the in , , and . In southern Africa, A. swazicum is endemic to (formerly Swaziland), southern , and adjacent areas in and . A. boehmianum inhabits dry regions of southern and northwestern to central . A. multiflorum ranges through southern tropical and , including , southeastern , , , , and northeastern . A. dhofarense is endemic to the Dhofar region of southern . A. somalense occurs in the , including , , and . Additional species, such as A. oleifolium, are confined to specific locales in and . Adenium species are widely cultivated globally as ornamental plants in tropical and subtropical climates and have become naturalized in parts of , including and . Their native ranges show stability shaped by .

Ecological Adaptations

Adenium species exhibit succulence as a primary to arid conditions, with their swollen and thickened stems serving as reservoirs for , allowing prolonged survival during droughts. This caudiform growth enables the plants to retain in underground or basal structures, minimizing the need for frequent uptake from scarce environmental sources. To enhance drought tolerance, Adenium plants often become deciduous during extended dry seasons, shedding leaves to reduce transpiration and conserve internal water reserves, while an extensive root system facilitates access to subsurface moisture in nutrient-poor substrates. This leaf drop, coupled with dormancy, helps the plants endure periods of water scarcity without permanent damage. Adenium thrives in well-drained, sandy or rocky soils typical of its native habitats, which prevent waterlogging and support aeration; some demonstrate tolerance to high and , enabling growth in coastal or mineral-rich arid zones. These preferences align with the plant's need for rapid drainage to avoid in low-rainfall environments. Ecological interactions further bolster survival, as the toxic latex exuded from stems and leaves contains cardiac glycosides that deter herbivory, providing without reliance on physical structures like spines. Additionally, Adenium forms associations with arbuscular mycorrhizal fungi, which enhance nutrient uptake—particularly —in phosphorus-limited arid soils, promoting overall resilience. In terms of , Adenium species endure temperatures ranging from 10°C to 45°C and annual rainfall as low as 200–600 mm, characteristics suited to the hot, dry savannas and scrublands of their distribution; this broad thermal tolerance, combined with low water demands, positions them as hardy components of fluctuating arid ecosystems.

Cultivation

Growing Conditions

Adenium species, commonly known as desert roses, thrive in conditions mimicking their arid native environments, requiring bright light, well-draining soil, and careful watering to prevent . They perform best in full sun, receiving at least 6 to 8 hours of direct daily, which promotes robust growth and prolific flowering; indoors, placement near a south-facing window is ideal to achieve this exposure. For optimal health, Adenium requires a well-draining mix, such as one formulated for cacti or succulents, incorporating , , or to ensure excess moisture escapes quickly; a range of 6.0 to 7.5 supports nutrient uptake without causing . Watering should be deep but infrequent, allowing the to dry completely between sessions, as these are highly drought-tolerant; during the winter period, reduce watering significantly or withhold it entirely to avoid rot. Temperature preferences align with warm, tropical conditions, with daytime ranges of 18°C to 30°C (65°F to 86°F) ideal for active growth and above 10°C (50°F) as a minimum to prevent damage; frost must be avoided entirely. Low humidity levels of 30% to 50% suit their succulent nature, reducing the risk of fungal issues common in humid settings. Fertilization during the spring and summer growth phase involves a balanced, diluted formula high in , such as NPK 10-30-20 at quarter to half strength, applied every two to four weeks to encourage blooming; withhold all fertilizers in winter. is typically done in spring to maintain a compact, bonsai-like form, removing dead or leggy growth after flowering to promote bushiness and airflow.

Propagation Methods

Adenium are commonly propagated through several artificial methods to produce true-to-type specimens, particularly for ornamental cultivars, as propagation often results in . These techniques leverage the plant's succulent nature and preference for warm, arid-like conditions to ensure successful rooting or . propagation involves fresh directly on the surface of a moist, well-draining medium such as a mix of and , without burying them deeply to allow exposure, which aids . Optimal temperatures range from 25-30°C, with typically occurring within 7-14 days under consistent and indirect ; success rates for viable can reach 70-90% when using fresh pods and applying a dusting to prevent damping-off. This method is straightforward for producing diverse seedlings but requires cross-pollination from different clones for set, as is rare. For cuttings, semi-hardwood stem sections of 10-15 cm are selected from healthy, mature growth, with the cut end allowed to dry for 1-2 days to seal the and reduce rot risk. The base is dipped in a rooting hormone like (IBA) at 8000 mg/L, then inserted into a sterile, aerated medium such as or a perlite-vermiculite blend under high (e.g., via misting or a propagation dome) at 25-32°C and moderate light levels of around 740 μmol m⁻² s⁻¹. Roots typically form in 4-8 weeks, with success rates of 85-100% in controlled conditions, though overwatering must be avoided to prevent basal rot. Grafting is a preferred technique for propagating hybrid varieties that may not easily from cuttings, using a compatible like A. obesum seedlings to provide vigor and resistance. Common methods include cleft or wedge , where a scion of similar (2-5 cm) is aligned with the 's layer and secured with tape or clips under sterile conditions at 25-30°C; success rates approach 80% in humid, shaded environments with application at the union. This approach accelerates establishment and preserves desirable traits like flower color. Air layering suits mature with thick branches, involving a cut to remove a 1-2 cm ring of bark and , followed by application of rooting hormone and wrapping the site with moist moss or held in place by and foil to maintain . Roots develop in 1-3 months in warm (above 25°C), humid conditions, after which the layered branch is severed and potted as a rooted cutting; this method yields high success for without sacrificing the parent plant. Despite these methods' efficacy, propagation challenges include the plant's inherently slow growth, often taking 1-2 years for propagated specimens to reach blooming size, and sensitivity to excess moisture, which can induce even in early stages—thus, well-draining media and careful watering are essential for all techniques.

Pests and Diseases

Adenium , particularly cultivated , are generally resilient but susceptible to several pests and diseases, especially in humid or poorly ventilated environments. Common issues arise from improper care, such as overwatering or inadequate airflow, leading to infestations or infections that can weaken the plant's and foliage. Among pests, feed on plant sap, causing leaf curling and distorted growth, and can be controlled with applications of . Mealybugs appear as white, cottony masses on stems and leaves, secreting honeydew that attracts ; treatment involves wiping them off with alcohol-soaked swabs or using sprays. Spider mites produce fine webbing and cause on leaves due to their sap-sucking activity, managed effectively with miticides or increased to disrupt their lifecycle. Scale insects manifest as armored bumps on stems and foliage, protected by waxy coverings; horticultural oils smother them when applied thoroughly to undersides. Diseases primarily include root rot, often triggered by overwatering and caused by fungi such as or species, resulting in soft, blackened roots and wilting; prevention focuses on improving soil drainage, while affected plants require root pruning and treatments. Powdery mildew presents as white, powdery coatings on leaves in high-humidity conditions, treatable by enhancing air circulation and applying . Anthracnose causes dark leaf spots and yellowing, typically from fungi, and is addressed by removing infected parts and using protective . To prevent pests and diseases, quarantine new plants upon arrival, monitor humidity levels to avoid excess moisture, and sterilize pruning tools with alcohol between uses. Introducing natural predators, such as ladybugs for aphid control, can provide biological management in outdoor settings. Additionally, the plant's milky latex sap is an irritant that can cause skin inflammation, so gloves should be worn during handling or pruning.

Uses and Toxicity

Ornamental Uses

Adenium species, particularly , are highly prized as potted plants due to their compact size and distinctive swollen , which lends itself well to training and creates an attractive, sculptural form. These succulents produce vibrant, trumpet-shaped flowers in shades of pink, red, and white, often blooming year-round in tropical conditions when provided with ample and well-drained . Their low-maintenance nature makes them ideal for indoor cultivation, where they can thrive as houseplants in containers, requiring protection from temperatures below 40°F (4°C). In , Adenium serves as a drought-tolerant accent plant in xeriscapes and rock gardens, particularly in warm climates such as USDA zones 10-11, where it functions as a striking specimen or small . Its ability to withstand heat and minimal watering enhances its suitability for low-water designs in regions like and , often displayed on patios or as focal points in arid-themed gardens. The plant's glossy leaves and profuse summer blooms add a tropical flair without demanding excessive care. Extensive varietal breeding has expanded Adenium's ornamental appeal through hybrids featuring enhanced flower colors, including double- and triple-petaled forms in multicolored varieties, achieved via crosses with species like A. swazicum. Grafting techniques further produce novel forms, such as bi-colored blooms and larger inflorescences, with significant advancements originating in , and refined in during the late . These developments have popularized Adenium in Asian gardens, where its resilience in arid conditions symbolizes adaptation to harsh environments. Container culture is key to enhancing the caudex's swelling, with mature specimens developing substantial basal thickening over 3-5 years when grown in wide, well-draining pots that accommodate root expansion. Regular repotting during the active (spring to fall) and full sun exposure promote this feature, resulting in dramatic, bonsai-like displays that highlight the plant's unique architecture.

Traditional and Medicinal Uses

Adenium species, particularly , contain cardiac glycosides such as oleandrin-like compounds throughout all plant parts, which can cause severe heart arrhythmias, gastrointestinal distress, and skin irritation upon contact. is potentially fatal, leading to rapid cardiovascular collapse. The milky latex exuded from wounds exacerbates skin irritation and is a primary vector for accidental exposure. In traditional African practices, root extracts of have been used as arrow poisons by groups such as the for hunting large game, leveraging the glycosides' potent cardiotoxic effects to immobilize prey quickly. The plant's spiny branches and inherent toxicity also make it suitable for constructing live fences to deter and intruders in arid regions of . Additionally, bark and leaf decoctions serve as fish poisons in communities across , , and , where the extract stuns aquatic life for easy collection. Medicinal applications in Yemen and parts of Africa involve diluted bark or root decoctions applied topically for treating wounds, edema, swellings, and venereal diseases, with careful preparation to mitigate toxicity risks. In the Sahel region, root decoctions, often combined with other plants, are used externally as lotions or baths for skin infections and inflammatory conditions. Preliminary studies have confirmed anti-inflammatory properties in leaf and stem extracts, attributed to phenolic compounds and glycosides that inhibit pro-inflammatory pathways in vitro. Due to its potent , is not recommended for and poses a significant risk as a veterinary , causing fatal arrhythmias in that graze on it. In some African cultural contexts, the plant's sap is incorporated into rituals believed to counter illnesses attributed to the , symbolizing protection against malevolent forces.

Conservation

Threats

Wild populations of Adenium species face significant threats from habitat loss driven by , , and urbanization across their native ranges in and the . For instance, A. swazicum has experienced rapid and ongoing habitat destruction due to conversion of sodic soils for and fruit cultivation, particularly outside protected areas like , with an estimated 20% decline in suitable habitat since 1990 and projected further losses of 30-40% by 2048. Similarly, on Socotra Island, A. obesum subsp. socotranum is impacted by and land clearance for development, which fragment rocky habitats essential for its survival. Overcollection for the international horticultural poses a severe risk, particularly to taxa prized for their caudiciform stems. Illegal harvesting targets mature of A. obesum subsp. socotranum from , where demand for ornamental specimens has led to unsustainable extraction of wild individuals, exacerbating population declines in accessible areas. In , A. swazicum suffers from for both medicinal uses and the succulent , with small, fragmented populations particularly vulnerable to removal of reproductive adults. Climate change intensifies these pressures by altering rainfall patterns and increasing drought frequency in semi-arid habitats. Reduced regeneration rates in Adenium species result from prolonged dry periods that stress seedlings and limit flowering, while shifting may disrupt the bimodal regimes critical for growth in regions like the and . For A. obesum subsp. socotranum, rising temperatures and erratic monsoons threaten the island's endemic ecosystems, potentially leading to . Competition from further hinders establishment of Adenium seedlings in degraded semi-arid environments. In southern African savannas, aggressive grasses and alien shrubs outcompete young for water and light, reducing recruitment success in already fragmented habitats occupied by A. boehmianum and A. swazicum. A. swazicum is regionally assessed as Vulnerable (SANBI 2018) due to habitat loss and exploitation, while A. obesum (including subsp. socotranum) and A. boehmianum are assessed as Least Concern on the global ; however, local declines are noted for several taxa owing to the cumulative impacts of these threats.

Protection Efforts

Adenium species face varying levels of threat, with some, such as Adenium swazicum, regionally assessed as Vulnerable (SANBI 2018) due to loss and illegal collection. Conservation efforts emphasize in-situ within natural s, particularly in protected areas across their native ranges. In , A. swazicum is safeguarded in reserves including and Timbavati Private Nature Reserve, where populations are monitored to mitigate and land conversion pressures. Similarly, Adenium obesum subsp. socotranum benefits from the World Heritage status of the Archipelago, which encompasses 11 terrestrial protected areas managed to preserve endemic succulent shrublands. These sites employ local rangers for patrolling and restoration, reducing risks from overgrazing and . Ex-situ conservation plays a key role in preserving genetic diversity for threatened Adenium taxa. Botanical gardens, such as South Africa's Lowveld National Botanical Garden, propagate A. swazicum through seed collection and cultivation programs aimed at public education and potential reintroduction. Studies on seed viability and germination have demonstrated high success rates—up to 100% under controlled conditions—supporting the establishment of living collections that serve as backups against wild population declines. While global seed banks like the Millennium Seed Bank have not specifically targeted Adenium, regional initiatives focus on succulent species, storing viable seeds to ensure long-term viability for restoration efforts. Research and breeding initiatives prioritize reducing reliance on wild-sourced plants through propagation techniques. For A. swazicum, integrated ex-situ and in-situ approaches include and seedling trials to bolster populations in sodic soils of and . Hybridization programs, though primarily ornamental, indirectly aid conservation by promoting cultivated varieties that decrease collection pressure on wild Adenium obesum and related subspecies. In , undocumented trials explore reintroduction of local Adenium variants, though challenges like arid conditions limit scalability. Community-based programs enhance monitoring and sustainable practices in Adenium habitats. In Yemen's , local councils co-manage protected areas, educating residents on non-destructive harvesting of endemic species like A. obesum subsp. socotranum, which is assessed as Least Concern but vulnerable to climate shifts. The International Union for Conservation of Nature (IUCN) supports regional assessments, with the last update for southern African succulents like A. swazicum in 2018 reflecting ongoing declines and informing adaptive strategies. These efforts foster community involvement in patrols and habitat rehabilitation, promoting long-term resilience for the genus.

References

  1. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:2172-1
  2. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:2172-1/general-information
  3. https://plants.ces.ncsu.edu/plants/adenium-obesum/
  4. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:76369-1
  5. https://tropical.theferns.info/viewtropical.php?id=Adenium+obesum
  6. https://pmc.ncbi.nlm.nih.gov/articles/PMC8241589/
  7. https://www.sciencedirect.com/science/article/pii/S2314853518302385
  8. https://www.dimmittadeniums.net/nomenclature-problems
  9. https://www.gbif.org/species/7155887
  10. https://pubmed.ncbi.nlm.nih.gov/2347008/
  11. https://pmc.ncbi.nlm.nih.gov/articles/PMC3841991/
  12. https://www.llifle.com/Encyclopedia/SUCCULENTS/Family/Apocynaceae/133/Adenium_obesum_subs._socotranum
  13. https://core.ac.uk/download/pdf/29381263.pdf
  14. https://landscapeplants.oregonstate.edu/plants/adenium-obesum
  15. https://apps.cals.arizona.edu/arboretum/taxon.aspx?id=1228
  16. https://journals.rbge.org.uk/ejb/article/download/1316/1207/4426
  17. https://plants.jstor.org/stable/10.5555/al.ap.flora.flota005448
  18. https://www.researchgate.net/publication/356876831_Adenium_Taxonomy_and_Nomenclature_Progress_Creates_More_Questions
  19. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:76360-1
  20. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77147984-1
  21. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:76366-1
  22. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77256107-1
  23. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:76370-1
  24. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:76374-1
  25. https://prota4u.org/protav8.asp?g=pe&p=Adenium+obesum+(Forssk.)+Roem.&+Schult.
  26. https://plants.ces.ncsu.edu/plants/adenium/
  27. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=276116
  28. https://www.researchgate.net/publication/359810996_Biology_and_structure_of_flowers_in_Adenium_obesum_Forssk_Roem_Schult_Apocynaceae_accessions_with_notes_on_the_significance_of_these_features_for_floriculture
  29. https://www.researchgate.net/publication/329413228_Adenium_obesum_as_a_new_potted_flower_Growth_management
  30. https://www.jstor.org/stable/42790026
  31. https://prota.prota4u.org/protav8.asp?g=pe&p=Adenium+obesum+(Forssk.)+Roem.&+Schult.
  32. https://powo.science.kew.org/taxon/77147984-1
  33. https://www.researchgate.net/publication/373196312_EXPLORING_THE_MYSTERIOUS_ADENIUM_OBESUM_ITS_BOTANICAL_APPEAL_ECOLOGICAL_SIGNIFICANCE_CULTIVATION_INSIGHTS_AND_POTENTIAL_MEDICINAL_APPLICATIONS
  34. https://extension.arizona.edu/sites/default/files/2024-08/az1953-2021.pdf
  35. https://dbg.org/wp-content/uploads/2021/02/DBG_Hort_GardeningGuides_Adeniums_Final.pdf
  36. https://edis.ifas.ufl.edu/publication/EP474
  37. https://www.gardenia.net/plant/adenium-arabicum-desert-rose-grow-care-guide
  38. https://mycorrhizae.com/wp-content/uploads/2017/03/Mycorrhizal-Status-of-Families-and-Genera-v1.6.pdf
  39. https://www.iplantree.com/does-adenium-obesum-need-sun-or-shade/
  40. https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/desert-rose/
  41. https://www.rhs.org.uk/plants/426/adenium-obesum/details
  42. https://ufdcimages.uflib.ufl.edu/UF/E0/04/46/97/00001/MCBRIDE_K.pdf
  43. https://www.thespruce.com/grow-desert-rose-plants-indoors-1902974
  44. https://ohiotropics.com/2022/08/26/desert-rose-dying-adenium-obesum/
  45. https://www.sciencedirect.com/science/article/abs/pii/S0261219422002344
  46. https://blackgold.bz/garden-questions-answered/what-is-causing-leaf-spot-and-drop-on-my-desert-roses/
  47. https://adenium.tucsoncactus.org/large.html
  48. https://pmc.ncbi.nlm.nih.gov/articles/PMC7748474/
  49. https://bushguide101.com/hadza-arrow-poison-made-from-adenium-species/
  50. https://www.sciencedirect.com/science/article/pii/S2543106421000041
  51. https://www.cabidigitallibrary.org/doi/pdf/10.5555/20123239752
  52. https://pmc.ncbi.nlm.nih.gov/articles/PMC9343940/
  53. https://www.merckvetmanual.com/toxicology/poisonous-plants/houseplants-and-ornamentals-toxic-to-animals
  54. https://www.plantsjournal.com/archives/2020/vol8issue5/PartA/8-4-30-191.pdf
  55. https://redlist.sanbi.org/species.php?species=997-7
  56. https://www.researchgate.net/publication/303857945_The_ecology_and_population_biology_of_the_critically_endangered_succulent_-_Adenium_swazicum
  57. https://www.linkedin.com/posts/organic-consumers-association-of-australia_biodiversity-nature-wildlife-activity-7037395500752412672-agee
  58. https://www.ourbreathingplanet.com/socotra-desert-rose/
  59. https://core.ac.uk/download/pdf/188771713.pdf
  60. https://www.academia.edu/105720127/Exploring_the_Mysterious_Adenium_Obesum_Its_Botanical_Appeal_Ecological_Significance_Cultivation_Insights_and_Potential_Medicinal_Applications
  61. https://www.worldfloraonline.org/taxon/wfo-0000763130
  62. https://sustainablebioresources.com/plants/plant-families/apocynaceae/adenium/adenium-socotranum/
  63. https://pza.sanbi.org/adenium-swazicum
  64. https://worldheritageoutlook.iucn.org/node/1154
  65. https://www.socotra-eco-tours.com/products/protected-areas/
  66. https://dewetswild.com/tag/adenium-swazicum/
  67. https://www.sciencedirect.com/science/article/pii/S0254629916337875
  68. https://www.kew.org/science/collections-and-resources/research-facilities/millennium-seed-bank
  69. https://adenium.tucsoncactus.org/sp_Tanzania.html
  70. https://www.researchgate.net/publication/303858034_The_critically_endangered_succulent_Adenium_swazicum
  71. https://www.krugerpark.co.za/krugerpark-times-6-1-poachers-target-impala-lily-25192.html
Add your contribution
Related Hubs
User Avatar
No comments yet.