Hybrids containing Adenium crispum & multiflorum

Adenium Sculptural Elegance, Floral Extravagance Adenium: Sculptural Elegance, Floral Extravagance, covers the cultivation and care of Adeniums, as well as their unique and attractive characteristics.The book showcases the beauty and ornamental value of Adeniums, and provides detailed information for both hobbyists and professional growers. The book is out of print, but you can download a 45 megabyte PDF; use the button below. Meet the Authors Corrections and Clarificatons Historic Letters Download PDF of Book Meet the Authors Authors from left to right: Dave Palzkill, Gene Joseph and Mark Dimmitt Mark A. Dimmitt has a Ph.D. in biology (zoology-herpetology) from the University of California at Riverside. He is retired from a 40-year career as a botanist/ecologist, mostly at the Arizona-Sonora Desert Museum. His second career is collecting and hybridizing plants, first Trichocereus (cacti) and Tillandsia (bromeliads). Since the late 1970s his main focus has been on breeding Adenium s. David A. Palzkill has a Ph.D. in Horticulture and Plant Pathology from the University of Wisconsin at Madison where he studied calcium-related problems of vegetable crops. Following fourteen years on the faculty of the University of Arizona, he consulted on alternative crops for dry regions and grew adeniums commercially for about 20 years. Gene E. Joseph studied Plant Sciences at the University of Arizona in Tucson. He was plant propagator at the Arizona-Sonora Desert Museum where he focused his interest in desert flora. He has run Plants for the Southwest, a desert plant nursery in Tucson, since 1986 Corrections & Clarifications Page 13, Figure 9: Photo was taken near Benoue National Park in northern Cameroon, not in Mauritania as stated in the book. Page 45, under Flowers header: The first sentence should read "The small flowers (Figure 105) are produced abundantly for about two months during late winter and early spring,... " Page 47, Figure 108: Pho to: Boris Vrskovy (Puk, with an accent on the y), not P. Mukundan. Page 65, Figure 44: The flower is 'Yolk Fragrance', purchased in Taiwan and photographed by Mark Dimmitt. Here is a picture of 'Arctic Snow', by David Clulow. Page 70, Figures 60 and 61: Photos are by David Clulow, not Ashish Hansoti as stated. Page 78, Figure 91: It's 'Harry Potter'; photo: Kenneth Wall. Page 96, Origin of 'Singapore': I rediscovered a lost note from Albert Chan and a letter from Frank Horwood dated 1980. Professor Holttum told Horwood that Adenium 'Singapore' was introduced to horticulture in Singapore in 1933, 50 years earlier than I had thought. (Richard Eric Holttum was Director of the Singapore Botanical Garden from 1926 to 1949, and later was on the staff of the Royal Botanical Gardens at Kew.) Chan's and Horwood's letters are archived here . Page 106, third paragraph: In fact, A. swazicum and A. oleifolium do experience freezing temperatures. Adenium oleifolium remains a short shrub partly because it is periodically frozen to the ground. Page 127, Figure 38: Photo: P. Mukundan, not Nathan Wong. Page 134: The Adenium "arabicum" at the bottom of the page is by Godong Ijo Nursery, not David Clulow. Clarifications Page 32: As stated, A. "arabicum" does indeed tend to grow short and squat at low, dry elevations and high, cold ones, and is often arborescent in wetter habitats. However, growth form is not only environmentally controlled; there is also a strong genetic influence. In cultivation some seedlings become shrubs with squat caudexes, while others grown in the same conditions become trees with tall, conical trunks. Page 47: The range of the unnamed Omani Adenium (A. dhofarense as of 2015) extends into eastern Yemen, near Hvai (Boris Vrskovy pers. comm.). The plants in Figures 108 and 109 are in fact from this location in Yemen, not in Oman as the caption states. The photos are also by Boris. Page 54: An adenium registry should go online soon. Stay tuned. (It never happened as of 2023) Species and Hybrid chapters . Flower shapes. Click here for an image gallery of flower shapes . Hybrid Chapter, page 70: After some discussion with Thai growers, it is apparent that most of their "arabicum" cultivars are in fact not cultivars. That is, their named plants such as 'Golden Crown', 'Petch Ban Na', Ra Chi Nee Pan Dok', etc. will not breed true either from seed or asexual means. This is because the names refer to particular growth forms achieved by careful pruning and training of the plants from a very small size. It is still unclear whether there is a formal nomenclatural term for this kind of plant. But they should not be called cultivars, and their names should not be enclosed in single quotes. Page 129, Table 2: When considering whether to water an adenium, it is important to know whether the plant is active or dormant. Click here for a gallery illustrating the terms dormant, active, and growing . Historic Letters

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 A. coetanum? 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 Lavranos' 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

Superior Cultivars of Adenium "obesum" x swazicum "Beauty Of Tiawan' 'Evelyn Marie' 'National Beauty' 'Calypso' 'Gemini' 'Pink Elegance' 'Volcanic Sunset' 'Crimson Star' 'Jade Lotus' 'Rainbow' 'Endless Sunset' 'Little Ruby' 'Red Ribbons' 'White Jade Peony' 'Beauty of Taiwan' (aka 'Taiwan Beauty') Parentage: Adenium "obesum" x A. swazicum complex hybrid. Creator: Unknown; Taiwan origin. Plant : Spreading shrub with lush foliage of large leaves. Known only as grafted plants? Evergreen? Flower: Circular, large. Color somewhat variable. Petals usually uniform light pink with very slight fading toward throat. Sometimes petals blush with slightly darker pink edge. Throat solid deep red. Renowned for blooming profusely. Notes: This cv. was popular in Bangkok, Thailand nurseries in 2000. It's exceptionally elegant and is hopefully still on the market. Above: A large specimen of 'Beauty of Taiwan' in Bangkok. This specimen is multiple grafts on a giant rootstock, probably somalense . Photo: Ashish Hansoti. Above: A young grafted plant of 'Beauty of Taiwan'. Above: The flowers of 'Beauty of Taiwan' vary somewhat with weather. Back to Menu Above left: 'Calypso' is a lush shrub whose foliage can conceal its branch structure. Above right: It can be pruned to create an erect shrub that exposes it sculptural form. 'Calypso' Parentage: Adenium "obesum" x swazicum complex hybrid. Creator: Richard J. (Jake) Henny, Florida, USA, ca. 1986. Plant form: Vigorous, spreading to drooping shrub with massive roots. Flower: Star-shaped, 82 mm diameter x 28 mm petal width. Petals brilliant pink, fading somewhat toward throat. Throat light pink with faint nectar guides. Flowers almost continuously. Notes: The pale throat of this cv. indicates that it is probably a second generation backcross to the "obesum " parent. This is one of the earliest named adenium hybrids, and still a plant worthy to be in collections. Back to Menu Left: Two photos of the brilliant flowers of 'Calypso' taken with different cameras and light conditions. 'Crimson Star' Parentage: Adenium "obesum" x swazicum primary hybrid. (A. "obesum " 'Red Everbloomer ' x A. swazicum 'Boyce Thompson ') Creator: Dimmitt, 1985. Plant form: A vigorous shrub with whitish bark, somewhat swollen main stems, and large roots. The foliage is a lighter green than of most adenium plants. Deciduous in winter unless kept very warm. Flower: Semi-star-shaped, 86 mm diameter x 25 mm petal width. Petals deep, solid crimson-red with almost no fading toward the throat. Throat deep red. Flowers 10 months a year, taking a break in midwinter. Notes: 'Crimson Star' and 'Grumbley White' were introduced to the horticultural world in Asia in the early 1990s. They showed that adenium flowers could be had in colors other than the common pink, and this triggered a surge in adenium popularity that continues today. The whitish bark and pale green leaves are diagnostic of this clone. Plants can be pruned to create a spreading shrub or an erect tree. This clone seems to have become senescent, in that cuttings no longer regain their youthful vigor as shown in some of the photos here. Cuttings and grafts grow weakly and don't develop the characteristic massive roots. If anyone has large specimens that were propagated after about 2000, please inform me. I know of no other adenium that has lost its vigor. Above left: a 10-year-old cutting of adenium 'Crimson Star'. This cv. has almost no caudex, but the trunk and main stems thicken nicely, as do the roots. Above right: 'Crimson Star' on a graft. These plants were trained as trees. Above left: a flower of 'Crimson Star' (bottom) with its parents A. "obesum " 'Red Everbloomer' (left) and A. swazicum 'Boyce Thompson'. This old scanned transparency is oversaturated. The photo above right is closer to 'Crimson Star's' color. Notice the centripetal fading of the petals of the "obesum " parent, and the solid color and characteristic dark throat of the hybrid. Above: a 4-year-old cutting of adenium 'Crimson Star', allowed to grow as a shrub. It's about 3 feet wide and was grown in pure peat moss. Adeniums aren't sensitive to potting medium as long as it's well-drained. This plant was grown in the 1990s. Today this clone has become senescent; cuttings no longer rejuvenate and grow this vigorously. Above: Adenium 'Crimson Star' grafted onto 'Arabian Ruby'. Photo: Kevin Barber. Back to Menu Above: Adenium flower color varies with temperature, becoming more pale with increasing temperature. 'Crimson Star' is one of the more sensitive; these flowers opened after a week of 110+ F (43+ C) weather. Above: The author with a 30-year-old cutting of adenium 'Crimson Star' in 2018. It died in 2022, apparently from being overpotted. Beware! Photo: Sarah Clark. Left: Aggressive rot consumed it Nothing lives forever.. Above: The original seedling of adenium 'Endless Sunset' at 14 years old. 'Endless Sunset' Parentage: Adenium "obesum " x swazicum primary hybrid (A. "obesum " 'Red Everbloomer' x A. swazicum 'Perpetual Pink') Creator: Dimmitt,1983. Plant form: Vigorous erect shrub, taller than wide; significantly swollen roots and main stems; evergreen. Flower: Round, 75 mm diameter x 35 mm petal width. Petals have bright pink edges, fading to medium pink at throat. Throat pink with no nectar guides. Flowers year round if kept warm. Notes: This F1 hybrid is unusual in that the fading petals show "obesum " dominance instead of the usual solid color of swazicum hybrids. Above: The flower of adenium 'Endless Sunset'. Back to Menu 'Evelyn Marie' Parentage: Adenium "obesum " x swazicum primary hybrid: (A. "obesum " 'Red Everbloomer' x A. swazicum 'Perpetual Pink') Creator: Dimmitt 1987. Plant form: Vigorous spreading shrub with fairly sturdy branches and immensely swollen roots. Evergreen. Flower: Circular, 78 mm diameter x 38 mm petal width. Petals deep pink with narrow reddish-pink margin; color fades to medium pink at throat. Throat pink with no nectar guides. Blooms year round under tropical conditions. Notes: Named in honor of my mother Evelyn Marie (Steele) Dimmitt. Above: Adenium 'Evelyn Marie', the original seedling at 17 years old. The plant is about 4 x 4 feet in a 24-inch pot. Above: My mother in 2000 with her new namesake adenium. Above: 'Evelyn Marie' grows a massive "caudex", which are actually roots. Above: The flower of adenium 'Evelyn Marie'. Back to Menu 'Gemini' Parentage: Adenium "obesum" x A. swazicum complex hybrid. Creator: Unknown, Taiwan. Plant form: Medium-size shrub with weak stems. Known only on grafts. Semideciduous winter rest. Flower: Star-shaped, large, 97 mm diameter x 26 mm petal width. Petals intense, solid crimson-red except for a white blaze at the petal bases. The blazes connect around the throat to create a starburst effect. Throat black with no nectar guides. Blooms over a long season. Notes: The white starburst helps to accent the intense color of this beautiful cultivar. This trait shows up occasionally in a wide range of hybrids. Above: A small specimen of 'Gemini' grafted onto an A. "arabicum" hybrid rootstock, in a 12-inch pot. Left and above: Doctor, my eyes! (Apologies to Jackson Browne) Back to Menu 'Jade Lotus' Parentage: Adenium "obesum" x A. swazicum ( complex?) hybrid. (or possibly x A. boehmianum ) Creator: Unknown, Taiwan Plant form: Lax spreading shrub with very large leaves. Known only as grafted plants. Flower: Large,circular, 82 mm diameter x 38 mm petal width. Petals uniform pale pink to nearly white depending on temperature. Throat red with no nectar guides. Notes: The big leaves suggest that one parent could be A. boehmianum instead of swazicum . However, this cultivar grows vigorously, and all of my hybrids with boehmianum grow very slowly. Also, I didn't see any A. boehmianum in Taiwan when I was there in 2008. Above: A small specimen of 'Jade Lotus' grafted onto an A. "arabicum" hybrid rootstock, in a 10-inch pot. Back to Menu Above: The flower color of 'Jade Lotus' varies from white to pale pink; probably temperature-related. Above: The original seedling of 'Little Ruby' at about 15 years old. 'Little Ruby' Parentage: Adenium "obesum " x A. swazicum primary hybrid. (A. "obesum " 'Red Everbloomer' x A. swazicum 'Boyce Thompson') Creator: Dimmitt 1985 Plant form : Vigorous spreading shrub with modest caudex development in age. Nearly evergreen. Flower: Smallish, semi-star, 69 mm diameter x 27 mm petal width. Petals crimson, fading slightly toward throat. Throat deep red with no nectar guides. Blooms almost year-round. Notes: The first crossing of these two parent plants produced 'Crimson Star' and 3 other excellent red-flowered clones; the rest were various shades of pink. 'Little Ruby' is similar to 'C Star', but has more floppy stems and smaller flowers. Right: The flower of 'Little Ruby'. Back to Menu 'National Beauty' Parentage: Adenium "obesum" x A. swazicum (complex?) hybrid. (or possibly x boehmianum ) Creator: J.F. Suen, Taiwan, before 2008 Plant form: A vigorous, upright to spreading shrub with very large leaves. Known only as grafted plants. Tends to be deciduous in winter. Flower: Very large, round to nearly circular, 91 mm diameter x 40 mm petal width. Petals vary from uniform intense crimson to purple, to purplish-pink in hottest weather and with age. Throat black. Flowers throughout the warm seasons. Notes: The big leaves suggest that one parent could be A. boehmianum instead of swazicum . However, this cultivar grows vigorously, and all of my hybrids with boehmianum grow very slowly. Also, I didn't see any A. boehmianum in Taiwan when I was there in 2008. Back to Menu Above left: grafted specimen of adenium 'National Beauty', 13 years old in a 15-inch pot. Above right: A triple-grafted plant of 'National Beauty'. The four flower images show variation in the color of 'National Beauty' in different temperature conditions. The deepest colors develop during hot weather, but below about 104 degrees F (40 C). 'Pink Elegance' Parentage: Unknown; Adenium "obesum" x A. swazicum hybrid, (probably backcrossed to "obesum ") Creator: Probably Dimmitt, before 2001 Plant form: A vigorous, upright shrub with a large pseudocaudex (swollen roots). Flower: Round, 85 mm diameter x 32 mm petal width. Petals light pink with narrow dark pink margin; color fades to near-white at throat. Throat red with no nectar guides. Blooms throughout the warm months. Notes: This cv. was found in a batch of seedlings grown by Gene Joseph of Plants for the Southwest Nursery. It grows well from cuttings and soon develops the big roots of the mother plant. Above: Flowers of 'Pink Elegance' Above: A cutting-grown plant of 'Pink Elegance' in a 12-inch bulb pan. The swazicum parentage really shows in the massive roots. Back to Menu 'Rainbow' Parentage: Adenium "obesum" x A. swazicum (primary?) hybrid. Creator: Unknown, Taiwan, before 2008. Plant form: A medium-sized shrub with weak, floppy stems. Known only as grafted plants. Evergreen, lush foliage. Flower: Round, very large, 107 mm diameter x 44 mm petal width. Petals uniform brilliant crimson; throat blackish-red. Blooms in two or three flushes during the warm months. Notes: The plant needs pruning every few years to maintain a compact form. Above: A new flower of 'Rainbow' (left) and a week-old one (right). Back to Menu Above: A grafted plant of 'Rainbow' in a 14-inch pot. 'Red Ribbons' Parentage: Adenium "obesum " x A. swazicum primary hybrid: (A. "obesum " 'Red Everbloomer' x A. swazicum 'Boyce Thompson') Creator: Dimmitt 1985 Plant form : A spreading shrub with sturdy main stems, no caudex, and moderately swollen roots. Nearly evergreen. Flower: Very large, star-shaped with long, narrow petals, 110 mm diameter x 30 mm petal width. Petals deep red-pink margins, fading to light pink at the throat. Throat red with no nectar guides. Blooms almost year-round. Notes: The first crossing of these two parent plants produced 'Crimson Star' and 3 other excellent red-flowered clones; the rest were various shades of pink. 'Red Ribbons' is similar to 'C Star', but has lighter colored flowers. Above: A cutting-grown 'Red Ribbons' in an 18-inch pot. Above: Flower of 'Red Ribbons'. Back to Menu Above: A cutting-grown 'Volcanic Sunset' in an 18-inch pot. 'Volcanic Sunset' Parentage: Adenium "obesum " x A. swazicum primary hybrid: (A. "obesum " 'Red Everbloomer' x A. swazicum 'Boyce Thompson') Creator: Dimmitt 1985 Plant form : A spreading shrub with sturdy main stems, no caudex, and moderately swollen roots. Nearly evergreen. Flower: Large, star-shaped, 95 mm diameter x 25 mm petal width. Petals deep red margins, fading to light pink at the throat. Throat red with no nectar guides. Blooms almost year-round. Notes: The first crossing of these two parent plants produced 'Crimson Star' and 3 other excellent red-flowered clones; the rest were various shades of pink. 'Volcanic Sunset' is similar to 'C Star', but has larger, lighter colored flowers. Back to Menu Above: The original seedling of 'Volcanic Sunset' at 14 years old in a 22-inch pot. 'White Jade Peony' Parentage: Adenium "obesum" x A. swazicum (complex?) hybrid. Creator: Unknown, Taiwan, before 2008. Plant form: A spreading shrub with lush foliage. Known only as grafted plants. Flower: Circular, 85 mm diameter x 40 mm petal width. Petals uniform brilliant white. Throat light yellow with dark base, no nectar guides. Blooms two or three times a year. Notes: A. swazicum parentage intensifies even white flowers. Above: A small grafted plant of 'White Jade Peony' in a 10-inch pot. Back to Menu Above: The flower of 'White Jade Peony'.

Back To Gallery Cultivars of Adenium oleifolium 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.

Flower Shapes Flower shape in adeniums is a continuum from very narrow-petaled (extreme star shape) to nearly perfect circles. The shape is complicated by other characteristics such as quilled (rolled) or ruffled petals. Shapes on a single plant can also vary with weather and cultural conditions. I like the definitions of the four shapes that I made up below, but it is often difficult to classify many flowers on the border between two types. Star-shaped Star-shaped flowers have such narrow petals that the free limbs (the part beyond the fused floral tube) barely if at all overlap with each other. They usually also have pointed petal tips. Nearly all flowers of Adenium multiflorum are star-shaped. Adenium crispum 'Famous Ancestor' flowers are typical for the species: star-shaped and quilled, with nectar guides far onto the petals. Adenium "obesum " 'Grumbley White' flowers are very star-shaped. It's from a wild collection. More modern whites have round to circular flowers. 'Colorful and Wonderful', a hybrid of "obesum " and crispum . Flower of an Adenium somalense growing in Bangkok. The petal tips are fairly rounded; this flower could be called a semi-star. An old A. crispum hybrid with very narrow petals. 'Black Raspberry', an "obesum"-crispum hybrid 'Crimson Star' is approaching a semi-star because of the wider petals. 'Success' is also nearly a semi-star. This plant has such weak stems that they hang vertically. Semi-star shaped Semi-star shaped flowers usually have pointed petals, but the petals are wide enough to overlap for up to half of their free lengths. Adenium "arabicum" Adenium "obesum " 'Black Ruby' Adenium "obesum " 'Daeng Siam' The flowers of the "obesum"-crispum hybrid 'Classical' are a bit pointy. The petal overlap is rather good, but the flower outline is not round. Most Adenium socotranum have semi-star shaped flowers. There is little petal overlap, but the tips are round. 'Rainbow' is an "obesum"-swazicum hybrid. The wide petals overlap well, but the pointed petals give it a semi-star shape. Round Round flowers have considerable petal overlap, and usually rounded petal tips. Adenium "arabicum " 'Hansoti Dwarf' Adenium "obesum " 'Amiability' 'Impressive #1' 'Pink Elegance', an "obesum"-swazicum hybrid, backcrossed to "obesum ". It's more difficult to describe the shape of Adenium "obesum" 'White Wave' because of the ruffled petals. It might be circular if the flower were flat. 'White Jade Peony', an "obesum"-swazicum hybrid with very flat petals. The tips are somewhat pointy, but the flower does not look semi-star shaped. Circular Flowers Circular flowers have rounded petal tips and very wide petals that overlap for well over half their lengths and nearly fill the circle they circumscribe. Perhaps there are not yet any truly circular adenium flowers, but the following cultivars at least come close. Adenium "arabicum " 'Yemeni Giant' has nearly circular flowers. This is excellent for a first-generation selection from a wild plant. Adenium boehmianum tends to have circular flowers. 'Evelyn Marie', a complex "obesum"-swazicum hybrid. Adenium "obesum " 'Home Run' 'Taiwan Beauty' (aka 'Beauty of Taiwan') is a hybrid of "obesum " with either swazicum or boehmianum . The ruffled petals of this Adenium "obesum " 'MAD 335' create an almost circular outline. Unfortunately, this blond color is unstable. A few of the normally purplish flowers bleach to this shade when they're a week old. Footnotes

Back to Gallery Cultivars of Adenium multiflorum 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 "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

Hybrids The vast majority of adenium hybrids are made with only three species: A. "obesum", swazicum, and crispum. I am working extensively with "arabicum" hybrids. Beyond those four, there is a small number of hybrids using other species. "obesum" x swazicum crispum x "obesum" "arabicum" x "obesum" "arabicum" x crispum "arabicum" x crispum x "obesum"

Taxonomy There are several species of Adenium , but the exact number is still unresolved. A recent DNA analysis of 5 mitochondrial, nuclear, and chloroplast segments (Dimmitt and Edwards 2021 ) identified seven well-defined species in three distinct clades (groups), and at least one more and perhaps several more species that could not be resolved. The three clades are shown in the graph below left, and their geographic distributions in the map below right. The horizontal lines in the cladogram are approximate measures of the distance between taxa (species or varieties) - the shorter the line, the more closely related the taxa. For example, in the Southern African group, A. boehmianum and swazicum are more closely related to each other than they are to oleifolium , and all 3 are quite distinct from the other 2 clades. The geographic distributions are drawn from limited herbarium records and the personal observations of John Lavranos. Adeniums do not occur continuously within these areas; there are many isolated populations. T he taxa in the Southern African and Arabian clades comprise six clearly defined species. The 3 Southern African species can be defined by their genetic differences alone, indicated by the fairly long horizontal lines between them. They are further distinct in having nonoverlapping geographic ranges. Adenium swazicum and A. boehmianum have very similar flowers, but these two species have very different growth forms, and occur on opposite sides of the continent. They're also geographically separated by A. oleifolium , which is phenotypically very different from the other two. Adenium swazicum (left) and A. boehmianum (center) have very similar flowers. They are unique in the genus in having uniformly colored petals (same shade from tip to throat), dark throats, and very short anther appendages. Both usually but not always have round flowers. But swazicum's leaves are narrow while those of boehmianum are very broad. The flowers of A. oleifolium (right) are quite different: small with nonoverlapping, pointed petals and long anther appendages. The 3 species in the Arabian clade are more closely related to one another than the taxa in the Southern African clade are related. Genetically (according to the 5 sequences analyzed) they could be considered a single species. But there are sufficient vegetative phenotypic and geographic differences to justify separating them. The flowers, however, have widely overlapping traits and are not reliably diagnostic. According to John Lavranos' field experience, Adenium "arabicum " (above left) and A. dhofarense (above middle) on the Arabian Peninsula are separated by a 100 km gap where no adeniums occur. They are also quite different in vegetative form. A. socotranum (above right) is isolated on a small, distant island, and can grow several times larger than any other adenum. The DNA clearly shows that this island giant is derived from the Arabian plants and not from A. somalense . Of the four taxa in the East African clade, Adenium multiflorum (above) is a distinct species. (Even though it is geogrphically in Southern Africa, it's genetically related to the other three far to the north.) Adenium "obesum", somalense , and crispum are a taxonomic problem. They were barely distinguishable by the 5 DNA segments that were analyzed, indicated by the very short horizontal lines between them. They appear to be a single genetic species. Plants of these 3 taxa in cultivation are phenotypically quite different and so are usually easily recognized. However, photos of wild plants show much more variation than we see in cultivation. Some examples of questionable identity are shown in the Other Taxa page. Furthermore, no adeniums from the vast Sahel region are known to be in cultivation, so their DNA could not be sequenced. The few photos available show that they have different vegetative and flower forms from the plants in East Africa. See the Other Taxa page. At this time it is not possible to determine whether the adeniums in this extensive region from East Africa through the Sahel are one highly variable species, or perhaps a multitude of isolated, closely related species. Flowers and leaves of Adenium "obesum " (left), somalense (center), and crispum (right) in cultivation look quite different. The plants are also distinctive (see species pages ). A. "obesum " is an erect or more often a spreading shrub with a modest caudex, and obovate leaves with faint veins. A. somalense has a massive conical trunk (but which is underground in sandy soil), and has elliptical leaves with prominent whitish veins (center inset). A. crispum is a dwarf shrub with linear, crisped leaves that also have prominent veins. But wild populations show much more variation than is seen in cultivation. See the Other Taxa and Unknowns page for details. Footnotes