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Other Taxa & Unknowns "somalense nova" "Thai Socotranum" Sahel Group Lake Eyasi mystery som. - crisp. intergrade A. coetanum? The Sahel Group Adeniums in the Sahel west of Ethiopia are of unknown identity. There are a few herbarium specimens, but no live plants in cultivation that are available for study. In photos the plants look much like A. somalense , but the leaves and flowers look more like those of A. "obesum ". If anyone has more photos or live plants from the Sahel (any country east of Ethiopia), please contact me . Above: Plants of Adenium sp. near Tintane (west of Nema), in southeast Mauritania; bush grassland. Plants from this region have been described as A. honghel ; there are no specimens available for study. Photos: Helene Jousse (via Jan Schlogl) Above: Plants and flowers of Adenium sp. near Tintane (west of Nema), in southeast Mauritania; bush grassland. Plants from this region have been described as A. honghel ; there are no specimens available for study. Photos: Helene Jousse (via Jan Schlogl) Above: Two plants of an Adenium sp. near Bénoué National Park, northern Cameroon. Plants west of here have been described as A. honghel ; plants to the east have been described as A. speciosum . There are no specimens available for study. Photos: Joel Peterson Back to Top Adenium speciosum? Left two: Plant and flowers of an adenium near Kauda, South Kordofan, Sudan. It looks similar to A. somalense in Ethiopia and Kenya, but plants from this region have been described as Adenium speciosum . Click to enlarge. Photos: submitted by Ricardo Denis. Adenium honghel? Left two: Adeniums near Bakel, Senegal. Right two: Adenium near Kedougou, Senegal; this is a mesic habitat for adeniums. Plants from this region have been described as Adenium honghel . The flowers at first appear to have dark throats, but they actually have pink throats overlain with very thick nectar guides. Click to enlarge. Photos: submitted by Ricardo Denis. Right two: Adenium near Yankari, Alkaleri, NG-BA, Nigeria. Plants from this region have been described as Adenium honghel . This plants's flowers look much like those above from Senegal. Again, the dark-appearing throats are caused by thick nectar guides. Photos submitted by Ricardo Denis. Adenium "somalense nova" This taxon was discovered in the mid 1990s in Tanzania, and is in the trade as Adenium "somalense nova". The name is enclosed in double quotation marks to indicate that it is not validly published. In nature the caudex is globular and buried underground, with erect, barely succulent stems to about 4 feet (1.2 m) tall. In cultivation seedlings develop a short-conical caudex that is partially exposed. The plants grow fairly rapidly and make a large caudex compared to the size of the plant in a few years. The small flowers start appearing sparsely at the end of the growing season in fall, followed by a more profuse bloom through the winter while the plants are leafless. They are pink to red at the edges, fading to a white throat with prominent nectar guides. The anther appendages protrude slightly beyond the tube. Another population that looks very much like this taxon has been found more than 100 km away. Adenium "somalense nova" collected in Tanzania. The caudexes were underground. Photo: Andre Williams Six-year-old seedling of Adenium "somalense nova" in a 16-inch pot beginning to flower at the end of the growing season. Six-year-old seedling of Adenium "somalense nova" in a 16-inch pot flowering during winter dormancy. Left and Right: Flowers of Adenium "somalense nova" . This group of Adenium "somalense nova" were grown by Hiren Vaghela. This distinct strain has very narrow leaves. Click to enlarge. Photos: Hiren Vaghela. Adenium "somalense nova" in the Wild Above: Adenium "somalense nova" east of Usambara Mountains south of Same, Tanzania. Right: Same plant with caudex excavated. This is a small plant. Photos: Chuck Hanson Back to Top Adenium "Thai socotranum" Adenium "Thai socotranum", also called "Thai soco", are not related to A. socotranum. They are in fact dwarf forms of A. "arabicum" bred in Asia. They are extremely popular, and there are many named varieties. See more examples in the Thai socos section in the A. "arabicum" page "Thai Socotranum" Photo: John Franklin Roosevelt Back to Top A. "obesum" near Lake Eyasi, Tanzania Anomalous adenium plants near Lake Eyasi, Arusha, Tanzania. This is in the geographic range of A. "obesum ", but the plants are unusually caudiciform. More important, the flowers are atypical of either species, but closely match those of A. swazicum or boehmianum hundreds of miles to the south. There is a population of these anomalous white-flowered, dark-throated adeniums growing on a rocky granite hill above a hot spring. Photos: David Bygott. NOTE: There are surely many other anomalous adenium populations in the wild. If you know of any, please contribute photos and other information to further our knowledge of these plants. Back to Top Right: ...and a gigantic specimen in the same locality. Click to enlarge. Photo: Chris Schmeling via David Bygott A. somalense-crispum intergrade? Adenium near Bulo Burri (Bulobarde), Somalia, between the ranges of somalense and crispum. The leaves appear to be linear and crisped like crispum, but this is a tree like somalense. What is it? These two taxa hybridize readily in cultivation. Photo: John Lavranos. Adenium coetanum ? An Adenium in the Dirashe District of southwestern Ethiopia, near the borders with South Sudan and Kenya. The plant is the size of A. somalense , and it occurs within the range of that species. But the leaves look like those of "obesum ", which begins in southern Kenya. The flowers appear to have dark throats,which, if true, is not characteristic of East African adeniums. This plant is not far from an herbarium specimen labeled A. coetanum . This plant also resembles the old cultivar 'Singapore ', which has been sold as A. coetanum . DNA analysis indicates that 'Singapore ' is an intergrade between A. "obesum " and A. somalense (Dimmitt and Edwards 2021 ). Photos: (contributed by Ricardo Denis). Left: This photo was taken in Ethiopia, where adeniums "should be" A. somalense . But the foliage and flower look like those of A. "obesum ". Perhaps this is what has been described as A. coetanum . Photo: Jim & Roxie Esterle Back to Top Footnotes

Species The genus Adenium consists of 11 phenotypically recognizable types in cultivation. There are at least 8 good species in nature, and perhaps several more (see map below). For ease of labeling, this site treats each type as a separate species, and I will use the names that are popular among horticulturists until the taxonomic confusion has been sorted out. Specific epithets (the second word in a binomial [scientific] species name) that have not been validly published and incorrect published names are enclosed in double quotes. (Very important: single quotation marks identify a cultivar name.) The taxonomy page summarizes what is known about adenium species, and the nomenclatural issues page summarizes the problems. See Dimmitt and Edwards 2021 for a detailed analysis. Adenium oleifolium swazicum boehmianum Southern African Clade socotranum dhofarense "arabicum" Arabian Clade multiflorum somalense "obesum" crispum East African Clade Ambiguous Taxa "somalense nova" "Thai socotranum" Sahel Group Lake Eyasi mystery som. - crisp. intergrade Approximate known distributions of Adenium taxa. The map was drawn from a rough sketch by John Lavranos, based on about 120 European herbarium records and his extensive field observations. Anchor 1 * 2021. Dimmitt, Mark A. and Taylor Edwards. Adenium Taxonomy and Nomenclature : Progress Creates More Questions. Cactus and Succulent Journal (U.S.). Vol. 3 no. 4, pp 252-266. Available as a PDF on request to the first author. Footnotes

Gallery of Superior Cultivars Intraspecific Cultivars "arabicum" boehmianum crispum dhofarense multiflorum "obesum" oleifolium socotranum somalense swazicum Interspecific Hybrid Cultivars "obesum" x swazicum crispum x "obesum" "arabicum" x "obesum" "arabicum" x "obesum" x crispum Rare Crosses Double Flowered Cultivars

Hybrids containing Adenium somalense nova & crispum Waiting for contributions

Superior Cultivars of Adenium crispum Back to Gallery 'Famous Ancestor' 'Famous Ancestor' (MAD106) Above: A specimen of 'Famous Ancestor' grafted onto a 3-foot tall rootstock 9 years earlier. A. crispum can grow large and fast when boosted by a vigorous rootstock. Above: The excellent flower of 'Famous Ancestor'. Few plants of this species have such bold nectar guides. Parentage: Adenium crispum Origin: Seed from a plant collected by Gerald Barad and Seymour Linden in the 1980s. Selected by Dimmitt in 1989. Plant form: Small, spreading shrub, typical of the species, with a small caudex and large swollen roots. Flower: Star-shaped, 40 mm diameter x 13 mm petal width. Petals strongly quilled, pink with very prominent extensions of the red nectar guides that extend all the way to the petal tips, and these are flanked by numerous fine red lines. Throat wide, white with prominent nectar guides. Blooms profusely in spring and sporadically in other warm months. Notes : This is the only known Ade nium crispum cultivar of importance. It is a major contribution to horticulture. This clone is evidently the ancestor of all adeniums with patterned flowers (splashes, blotches, and stripes). See Dimmitt, Joseph, and Palzkill 2009 for details. Left: The wild-collected seed parent of 'Famous Ancestor'. The fusiform caudex is typical of the species, and was below ground. In cultivation most seedlings develop multiple succulent roots. Back to Menu

Back to Gallery Cultivars of Adenium boehmianum None? I don't know of any selected cultivars of this species that are important to adenium horticulture. If you know of any, please submit photos and a description using this form . Due credit will be given.

Adenium somalense Stapf Adenium somalense occurs in Somalia, Ethiopia, Kenya, and a bit into adjacent nations. The most common form in cultivation grows a tall, conical, succulent trunk, but there are also shrubby forms with subterranean caudexes. Only A. "arabicum" and socotranum have larger caudexes. The most identifiable vegetative characters are the conical caudex and light-colored veins in the leaves. The flowers are rather small, 1 to 2 inches wide. The flowers typically have narrow pointed petals (star-shaped flowers) that are white or pink with dark pink or red borders. Prominent nectar guides in the throat extend onto the petals as fainter lines, not as bold as those of most A. crispum flowers. It is not common in cultivation in the USA, but is fairly popular in more tropical countries. Adenium somalense in a 30-inch pot at a nursery in Bangkok, Thailand; the plant is 10 years old. The cutting at the base is in a 4-inch pot. Adenium somalense grown in Tucson, Arizona. It's 9 feet tall at 17 years old from seed, but has lost its roots to rot twice because of cold weather. The plants I have from Shaba National Park in Kenya are very prone to root-rot. Note the 12-inch ruler at the base. Flowers of 2 Adenium somalense clones from Shaba N.P., Kenya. The nectar guides of the flower above extend onto the petals. Two large A. somalense in a Bangkok, Thailand nursery. A multi-trunked specimen of A. somalense in Tucson, Arizona. Note the 12-inch ruler. A collected plant of the sand form of A. somalense in Tucson, Arizona. Notice the roots near the top of the bulbous caudex; these were just below the surface in nature. A fat specimen of A. somalense breaking its pot in Tucson, Arizona. An arborescent A. somalense in Tucson, Arizona. Not all clones grow huge trunks, either in nature or cultivation. Back to Top Adenium somalense in the Wild Adenium somalense east of Bargal, Somalia. Photo: Myron Kimnach Adenium somalense east of Bargal, Somalia. Photo: Myron Kimnach Adenium somalense near Bargal, Somalia. Photo: Myron Kimnach Anton Ellert next to an Adenium somalense near Lake Borgoria, Kenya. Photo: Robert H. Webb Toni Yocum next to an Adenium somalense in Kenya. Photo: Robert H. Webb Toni Yocum in an Adenium somalense in Kenya. Photo: Robert Webb Toni Yocum next to an Adenium somalense in Kenya. Photo: Robert H. Webb Above two: Two old A. somalense in Ethiopia. Photos: Jim and Roxie Esterle Above: A monstrous specimen of Adenium somalense in Ethiopia. Inset: the flower. Photo: Jim & Roxie Esterle. Above & right: It isn't certain that all of these plants in Ethiopia are Adenium somalense . Some of the flowers look more like those of the unknown taxa in the Sahel . Photos: Jim & Roxie Esterle. Right: The foliage and flower look those of A. "obesum ", or possibly A. coetanum . Photo: Jim & Roxie Esterle. Adenium somalense near Lake Baringo, Kenya. Photo: Boris Vrskovy. Adenium somalense in full bloom near Hola, Kenya. Photo: Rainer Martin (sent by Boris Vrskovy). Adenium somalense in Ethiopia. Photo: Boris Vrskovy. Three above: Flowers of Adenium somalense in Ethiopia. The center one is in Mago National Park NE of Lake Turkana. Photos: Boris Vrskovy. Above and Right: Adenium somalense near Lake Baringo, Kenya. Photos: Gaetano Moschetti. Above: Adenium somalense near Lake Baringo, Kenya. Photos: Gaetano Moschetti. Left and above: An enormous Adenium somalense near Lake Baringo, Kenya. It's surrounded by a colony of Sanseveieria with 6-foot tall leaves. Photos: Gaetano Moschetti. A shrubby Adenium somalense on the Yabelo-Konso road in SW Ethiopia.. Photo: Gaetano Moschetti. Left and above: A beautiful, red-flowered Adenium somalense in Kenya. The nectar guides extend unusually far onto the petals. Photos: Gaetano Moschetti. Left and above: Two enormous Adenium somalense specimens in Kenya. Photos: Rob Skillin. An isolated Adenium somalense on the ascent to Celdora Pass from Las Korei, Somalia. Photo: John Lavranos. Above: The sand form of Adenium somalense in northern Somalia. Most of the large caudex is below ground. Photo: Thomas Price. Left & below: Adenium somalense between Erigabo* & Burao** , Somaliland. Photo: Boris Vrskovy (Puk). Above 3: Adenium somalense near Karinga, Kenya, ca. 70 km north of Nairobi. (The very different appearing shrubby Adenium "obesum " occurs about an equal distance southeast of Nairobi.) Photos: Boris Vrskovy (Puk). Back to Top Footnotes Erigabo, also spelled as Erigavo and Ceerigaabo. Burao, also spelled Burrao, Bur'ao, and Burco.

Adenium crispum Adenium crispum occurs in a band of sandy soil near the coast of southern Somalia. (It has not been formally published as a full species, but as A. somalense var. crispum Chiov.) In nature the fusiform caudex is subterranean. Most of the root system arises from near the top of this caudex. In cultivation the caudex is raised above soil level, and the caudex reroots from the bottom. The stems are thin and rarely exceed a foot tall. The small flowers are very distinctive and serve as the best identifier: most clones have quilled petals (curled longitudinally). And most notably, the nectar guides extend well onto the petals, often all the way to the tips. (The flowers of some A. somalense have nectar guides onto the petals, but the petals are only slightly or not at all quilled.) The anther appendages often extend beyond the throat. Flat-petaled and solid red-petaled plants are known. It is not widely cultivated, probably because it is very cold-sensitive and intolerant of hot, humid weather. Adenium crispum , a collected plant. Note the scars from the original roots near the top of the caudex. An unusually tall A. crispum . W hen grafted onto a large rootstock, Adenium crispum can grow huge. This 5-year-old graft of 'Famous Ancestor ' is more than 2 meters tall, half of which is the rootstock. 4 years old in a 6-inch pot. 10 years old in a 12-inch bonsai pot. Above 3 photos: seed-grown Adenium crispum 'MAD 297', showing its slow growth through the years. 22 years old in a 16-inch bonsai pot. Flower of A. crispum 'Famous Ancestor ' with especially prominent, long nectar guides and strongly quilled petals. Back to Top A selection of Adenium crispum flowers in cultivation, showing variation in petal color, shape, and nectar guides. Adenium crispum in the Wild Adenium crispum near Warshak, Somalia Photo: Myron Kimnach Adenium crispum 40 km north of Mogadishu, Somalia on road to Warshedih Photos: John Lavranos Adenium crispum 40 km north of Mogadishu, Somalia on road to Warshedih. Photo: John Lavranos Two plants of Adenium crispum with solid red flowers. Above left: Somalia, location unknown. Photo: John Lavranos Above right: 40 km north of Mogadishu, Somalia. Photo: Gerald Barad. John Lavranos displays a recently collected plant of Adenium crispum in Somalia. Note the feeding roots on the top of the subterranean caudex. Photo: John Lavranos Back to Top Footnotes

Adenium "obesum " Roem. & Schult. Adenium "obesum" occurs in southeastern Kenya, eastern Tanzania, and northeastern Mozambique. The specific epithet is enclosed in double quotation marks because it's an incorrect name. See the nomenclature issues page for explanation. Cultivated plants of Adenium "obesum" are usually spreading shrubs with weak branches that tend to droop. Some selected cultivars are upright. Most plants have poorly developed caudexes, but a few will produce big ones with time. The flowers are the largest in the genus, typically 2 to 3 inches in diameter, and some cultivars exceed 4 inches. Petal color of wild plants is usually pink on the margins, gradually fading to white at the white or yellow throat. Modern cultivars display a wide range of brilliant colors, some with little or no fading toward the center. Flowering peaks in spring, with a smaller peak in autumn. The best cultivars are nearly everblooming. Nectar guides in the throat are usually faint or absent. The anther appendages extend to the edge of the throat or a little beyond. This is the only species that does not have a requisite winter dormant period; it can grow year round under tropical conditions. Even if dried out in winter, it tends to remain evergreen. Adenium "obesum" and its hybrids are the most common adeniums in cultivation. They have been highly selected, and are now available in a wide range of colors, including white, purple, red, and yellow. There are also bicolors, double flowers, and mutants with variegated or colored leaves. See the gallery of superior cultivars for examples of modern varieties. Above: A typical wild type Adenium "obesum" from the early 1980s. Notice the pink flowers and neglible caudex. This plant is much more upright than is typical of the species. See flower below. Above: A. "obesum" 'Red Everbloomer ', a 4-year old cutting. Image below is its flower. This is a Dimmitt selection resulting from 3 generations of breeding darker-flowered plants. Above: A. "obesum" 'Red Cloud', a Taiwan selection from 2000. The Taiwan Red strain typically has large, shiny green leaves. There are many cultivars with superb red flowers. Flower closeup is below. Above: Flowers of a typical wild type A. "obesum" . Other colors are rare in the wild. Note the fading of petal color toward the throat in all of the images of this species. Above: A. "obesum" 'Red Everbloomer '. When it first flowered in 1980, it was an excellent and exciting new color. Today it's mediocre. This is how far adenium breeding has come in 25 years. Above: A. "obesum" 'Red Cloud'. This was the best plant from 1000 seeds imported from Taiwan in 1999. See plant above. Above: A. "obesum " 'Black Ruby '. This clone flowers profusely and develops a tall, conical caudex; the plant is a 7 year old graft (the rootstock has been cropped off the image). It appears to be of the Taiwan Red strain, but it is more cold tolerant than most of those plants bred in the tropics. Above: Flower of A. "obesum" 'Black Ruby '. This cultivar was discovered in the early 1990s in a Florida nursery by James Georgusis. Beyond that its origin is unknown. The flower quality has been surpassed by numerous Taiwan selections, but this is still a great plant because of its substantial caudex, which is cylindrical or narrowly conical. Above: A. "obesum " 'Incandescent'. This is an offspring of 'Black Ruby' bred by Dimmitt in 2001. A. "obesum " 'Incandescent' flowers profusely nearly year-round. A. "obesum ", a good early pink cultivar bred by Ashish Hansoti. A. "obesum" 'MAD #286', a pink picotee with yellow throat bred by Dimmitt from Ashish Hansoti stock A. "obesum " in Vietnam. The one on the left shows the species' typical lack of a caudex. These plants have been potted higher to expose the thick roots. The plant on the right has developed a succulent trunk, which is technically not a caudex. Photo: Bev Tall. These two screenshots are from the 1971 Bruce Lee martial arts movie Big Boss (aka Fists of Fury). The final scene was filmed on an estate in Thailand, where there were numerous potted A. "obesum " around the property. Adeniums were very rare in cultivation that long ago. All of the plants are very similar - non-caudiciform shrubs with pink flowers. They're probably the same clone, grown from cuttings. Above and right: Ashish Hansoti's Tropica Nursery near Mumbai. Photos taken in 2008 of his collection of A. "obesum " that he acquired during the 1980s. There was very little diversity in adeniums at the time. Photo on right: Kevin Barber. Back to Top Above: John Lucas at his Tradewinds South Nursery (Florida) pollinating his huge specimen of A. "obesum " 'Big Mama' in the 1990s. This plant appears to have a true caudex between the roots and stems. Adenium "obesum" in the Wild Above and right: Adenium "obesum" near Nairobi, Kenya. The caudexes are underground. Some of these wild plants can be underwhelming. Photos: Robert H. Webb Above: Adenium "obesum" near Mombasa, Kenya. Photo: Gaetano Moschetti Above: Adenium "obesum" near Mombasa, Kenya. Photo: Gaetano Moschetti Above: Flowers of an Adenium "obesum" near Mombasa, Kenya. Photo: Gaetano Moschetti Above: Adenium "obesum" near Lake Natron,Tanzania. The usually subterranean roots have either been exposed by erosion, or because the plant is growing in rocky ground. Photo: Robert H. Webb Above: Adenium "obesum" near Samburo West, Kenya. The petals are darker than is typical of the species. Photo: Robert H. Webb Above: Adenium "obesum" near Salaita Hill, Kenya. Photo: James Culverwell. Back to Top Above: Adenium "obesum " "Mombasa form", grown from seed collected from the well-known population along the Nairobi-Mombasa road, Kenya. 1. This population is known to grow large caudexes. 2. Not all wild adeniums have beautiful flowers. Photos: David Palzkill. Footnotes

Cultivation What is Dormancy? What is Actively Growing? Adenium "arabicum " cultivar 'MAD 965' Adenium Culture Characteristics of Adenium Species Anchor 1 Download PDF: Anchor 2 Download PDF: Dormancy In botany, "dormant" means not actively growing. Dormant plants may retain leaves and still conduct photosynthesis, and they may also flower. Dormant and deciduous. Water consumption is nearly zero. Adenium "arabicum". In leaf, but dormant because no new leaves are being produced. Adenium "obesum". Water such plants sparingly; it doesn't consume much in this state. In leaf, but dormant because no new leaves are being produced. Adenium "obesum". Water such plants sparingly; it doesn't consume much in this state. Dormant and deciduous, but flowering. Water use is still minimal. Adenium "arabicum" 'Hansoti Dwarf'. In leaf and flowering, but it's still dormant because no new leaves are being produced. This plant uses much less water than when it is growing new stems. Adenium "arabicum" In some adeniums part or all of the foliage will suddenly turn yellow and fall. This plant has entered dormancy and watering must be sharply reduced or stopped. Adenium crispum X "obesum" hybrid 'New Star'. The dormant plant is flanked by two other crispum hybrids that are still actively growing. Growing and Active In botany, "dormant" means not actively growing. Dormant plants may retain leaves and still conduct photosynthesis, and they may also flower. This Adenium socotranum is breaking dormancy. Water use is still low, but it needs some to stimulate waking up. This 'Arabian Ruby' was evergreen through the winter, and is now breaking dormancy by producing new leaves in spring. Growing: The soft green stem of this 'Crimson Star' reveals active stem elongation as well as rapid new leaf production. This 'Arabian Ruby' was evergreen through the winter, and is now breaking dormancy by producing new leaves in spring. Active. Not dormant, but not really growing either. If kept warm and moist in winter, some adeniums continue making new leaves at a slow pace, but stem elongation is minimal. Water use is much less than during the summer growing season. Footnotes