Hoodiopsis triebneri
Plant Family
Apocynaceae – Dogbane Family.
Note: This species was formerly in the family Asclepiadaceae (milkweed family) that is now treated as the subfamily of Asclepiadoideae in the family Apocynaceae.
Binomial Name
Hoodiopsis triebneri C.A.Lückh
Synonymous Binomial Names
×Hoodialluma triebneri (Luckh.) G.D.Rowley
×Hoodiorbea triebneri (C.A.Lückh.) G.D.Rowley
Hoodiopsis triebneri was first described and named as a species in 1933 (Lückhoff 1933). It is now regarded as a naturally occurring intra-generic hybrid of Hoodia gordonii and Orbia (Orbeopsis) lutea subsp. vaga (Bruyns 1993). International codes specifying rules for botanical nomenclature indicate that intrageneric hybrids should be named. Hoodiopsis triebneri C.A.Lückh remains an accepted taxon in the Global Biodiversity Information Facility (GBIF) and other databases of recognized plant names.
On this website and in our research reports we will regard Hoodiopsis triebneri as a distinct species and may refer to it as just Hoodiopsis since there are no other species in the genus.
Common (Vernacular) Names
None known.
Plant Characteristics
Endemicity. An intra-generic hybrid species endemic to a large area extending from Namibia to the North Cape province of South Africa, usually as repeated occurrences of solitary individuals. This distribution pattern in hybrid stapeliads may be typical of situations where there is wide sympatry of the parent species (Bruyns 2005b).
Growth Habit. A perennial succulent with stems reaching a maximum height of about 10cm off the ground. The stems have 7 to 9 tuberculate angles and no leaves. A detailed description of the morphology of this species is available (SANBI 2018).
 Hoodiopsis triebneri |
Crestate Forms. Crestate stems have spontaneously formed on several of our Hoodiopsis plants. These are the first crestate forms reported in this species. Crestate plants have an uncontrolled growth pattern and can become much larger than plants of normal form. The largest of our crestate Hoodiopsis plants was transferred to a specialist grower in Arizona to attempt production of additional crestate plants from cuttings.
Formation of a crestate stem from one bud.
 Hoodiopsis, Crestate Stem Forming |
 Hoodiopsis, Crestate Stem Bud, Close Up |
 Hoodiopsis, Massive Crestate Stem |
Crestate Reversal. Stems of normal form can grow out of a crestate plant. Eventually, most of the crestate tissue vanishes as the normal stems grow out of it. The sequence of photos below shows the stages of reversal of a completely crestate cutting of Hoodiopsis to a plant consisting of only normal stems.
Reversal of a crestate stem into multiple normal stems.
 Hoodiopsis, Beginning of Crestate Stem Reversal |
 Hoodiopsis, Partial Crestate Stem Reversal |
 Hoodiopsis, Complete Reversal of Crestate Stem |
Flowers. The flowers form on peduncles, are usually star-shaped but their shapes on the same plant may be variable, some appear as irregular shapes and incomplete stars. Flower shape may also be highly variable among plants from different sources. The photo of a Hoodiopsis flower from the eastern foot of the Great Karas Mountains in Nambia (Bruyns 2005b) shows a corolla with long, slender star points, a form never observed on our plants.
 Hoodiopsis, Flower Bud |
 Hoodiopsis triebneri, Flower |
 Hoodiopsis triebneri, Flower Center, Macrophotograph |
On warm days Hoodiopsis flowers emit a fetid odor similar to that of the large flowered hoodias and attract many species of flies. Our plants bloom throughout the year but pollination rarely occurs.
Fruit. The fruit consists of two horn-like follicles. As they mature the follicles dehisce along sutures releasing numerous seeds with pappi that open up on release like umbrellas and become airborne.
 Hoodiopsis, Ripening Follicles |
 Hoodiopsis, Follicle Releasing Seeds |
 Hoodiopsis, Single Seed, Airborne |
Seeds. The seeds are light brown and typical in form to other stapeliad seeds. Most of the seed lots produced from our plants have not been viable.
 Hoodiopsis, Single Seed with Pappi Fully Open |
Introgressive Hybridization? Flies have been observed to visit the flowers of Hoodiopsis and hoodias blooming at the same time in our greenhouses. One batch of viable seeds produced from Hoodiopsis yielded seedlings of similar form to the parent plant but much taller, more like Hoodia. This suggests that the pollinator may have been a hoodia species and that the seedlings could be introgressive hybrids.
Conservation Status
No information on the conservation status of this hybrid species was found. Assuming Hoodiopsis may not be producing much viable seed in the wild its status may follow that of its putative parent species, Hoodia gordonii and Orbia lutea subsp. vaga.
CITES Listing: Hoodiopsis triebneri is not listed on any of the CITES Appendices . However it is regulated as a hybrid of a species listed in Appendix II:
The species taxon name Hoodiopsis triebneri does not appear on any of the CITES appendices (CITES 2018). However, since this plant is probably a naturally occurring hybrid of Obeopsis leutea subspecies vaga and Hoodia gordonii (Bruyns 2005b), a species included in Appendix II, it is subject to CITES controls. CITES Resolution Conf. 11.11 (Rev. CoP17) on Regulation of trade in plants, paragraph 6, regarding hybrids-
- DETERMINES that:
“a) hybrids shall be subject to the provisions of the Convention even though not specifically included in the Appendices if one or both of their parents are of taxa included in the Appendices, unless the hybrids are excluded from CITES controls by a specific annotation in Appendix II or III;”
Hoodia gordonii is listed in Appendix II and the annotation does not exclude hybrids, exports of the hybrid Hoodiopsis triebneri are regulated under CITES (FWS 2019). Since there are no exemptions for the seeds of Hoodia species CITES controls are assumed to also apply to the seeds of Hoodiopsis triebneri.
IUCN Listing: No assessment of this species was found on the IUCN Red List of Threatened Species™ [IUCN 2018].
U.S. Endangered Species Act Listing Status: This species is not listed (FWS 2018).
Uses
Ornamental Plant. Hoodiopsis plants are rarely available and have been grown to a very limited extent as ornamental succulents. They are drought tolerant and may have some limited potential for use in xeriscaping of semi-shaded areas.
Traditional Medicinal Uses. A literature search yielded no reports of medicinal uses of this plant.
Research Interests. We have been growing this plant for our research and evaluating the feasibility of larger scale production should the need arise. Investigations into the potential presence of anorectic compounds in this species were recently concluded and we may publish our findings soon. Other research activities relating to development of consumer products from this plant were also conducted. These were described in a provisional patent and will be retained as proprietary information. The results from this research and continuing difficulties in managing plant diseases have been discouraging. No additional research is planned and most of our remaining plant inventory will be released for sale.
Cultivation
A small number of Hoodiopsis plants have been grown by collectors and botanical gardens but the species is rare in cultivation. Over the last several years we have produced several hundred plants at our Maryland and Hawaii nurseries from cuttings. Most of these were lost to plant diseases or consumed by our research activities.
Propagation
Seeds. We have successfully grown Hoodiopsis from seed but most of the few lots of seed that we have produced have low or no viability.
Cuttings: Hoodiopsis is easy to propagate from cuttings. Prepare fresh cuttings and allow several hours for the cutting wounds to dry. Then plant them very shallow or place them directly on the surface of a sterile, sandy rooting media. Keep the media most but not wet. A significant percentage of the cuttings may be lost to soft rot. To minimize transmission of bacteria from infected plants keep the plants in separate pots. Roots usually form within a month. Transplant the rooted cuttings to clean potting soil like the commercial mixes intended for growing cacti. The plant does best in partial sun and warm temperatures.
Improved Cultivars
We attempted to develop more disease resistant cultivars of this plant but abandoned this effort.
Pests and Diseases
Hoodiopsis is highly susceptible to the same pests and diseases that commonly affect other asclepiad plants.
Anthracnose Fungus. Most of the Hoodiopsis plants we grew outdoors in Hawaiʻi and in the summer months in Maryland eventually contracted anthracnose fungus (Colletotrichum spp.) which will eventually kill the plants. The fungus is probably spread by mites, mealy bugs and rain. Prolonged moist conditions as are typically in the rainy season here favor transmission and growth of the fungus. There are also numerous host plant species that harbor it. Because our hoodiopsis plants were being grown for research and potential nutraceutical applications we could only use organic pesticides to control the fungus. Sulfur emulsions and neem oil are not effective. No effective preventative measures or treatments were found and we have concluded that this species cannot be grown successfully as a crop outdoors. Hoodiopsis grows well in our greenhouses and does not get anthracnose.
 Anthracnose on Hoodiopsis Stem |
 Anthracnose Decimates Flat of Hoodiopsis Cuttings Grown Outdoors |
Bacterial Soft Rot. Hoodiopsis is highly susceptible to soft rot. In this species it usually begins in the roots or the stems near the soil surface. Affected plants tend to break off above the affected area. Unlike the rapidly spreading soft rot syndrome commonly affecting Hoodia species, these infections seem to be isolated in the affected area. A callus-like barrier forms around the site. The remainder of the plant appears to be unaffected and can be re-rooted.
 Soft Rot of Hoodiopsis triebneri |
Mealy Bugs. Mealy bugs are severe pests of this species when grown indoors. Insect soap, alcohol and neem oil extracts provide effective control.
 Mealy Bugs on Hoodiopsis |
Invasiveness Potential
The high susceptibility of this species to ubiquitous pests and diseases, and low production of viable seeds suggests a low risk of invasiveness in Hawai‘i.
Hawai‘i-Pacific Weed Risk Assessment (HPWRA) Program. Hoodiopsis triebneri has not been accessed by the program. However, Hoodia gordonii a putitive parent of this hybrid species has been accessed and assigned a low risk rating score of 0, indicating low risk.
Global Invasive Species Database Listing. Hoodiopsis triebneri was not found on the database (GISD 2018).
Plants and Seeds for Sale
Availability
Seeds. Seeds from lots in our current inventory appear to be non-viable and production of new seeds from our existing plants is unlikely.
Nursery Stock. We offer non-certified, rooted cuttings of this species from our online store.
Shipping Information
Our non-certified Hoodiopsis plants cannot be shipped to the states of Arizona, California, Louisiana and Texas.
References
Albers F, Meve U, eds. 2002. Illustrated Handbook of Succulent Plants. Dicotyledons. Asclepidaceae. 1st edition 2002, corrected second printing. Albers F, Meve U, eds. Berlin, Germany: Springer-Verlag. ISBN 3-540-41964-0.
Barad GS 1990. Pollination of the stapeliads. Cact. Succ. J (US) 62:130-140. Cited in Bruyns (2005b).
Bruyns PV. 1993. A revision of Hoodia and Lavrania (Asclepidaceae- Stapeliae). Bot. Jahrb. Syst. 115:145-270. Cited in Bruyns (2005b).
Bruyns PV. 2005a. Hoodia. In: Stapeliads of Southern Africa and Madagascar. Vol 1, Chapter 4. Hatfield, South Africa: Umdalus Press.
Bruyns PV. 2005b. Hybrids. In: Stapeliads of Southern Africa and Madagascar. Vol 2, Chapter 21. Hatfield, South Africa: Umdalus Press.
CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). Appendices I, II, and III valid from 4 October 2017. https://www.cites.org/eng/app/appendices.php [accessed 18 October 2018].
FWS (U.S. Fish and Wildlife Service). 2018. Endangered Species Home. Search Endangered Species Database. https://www.fws.gov/endangered/ [accessed 18 October 2018].
FWS (U.S. Fish and Wildlife Service). 2019. E-mail communication, July 3, 2019 from Heather Harcum, Permits Biologist, International Affairs, U.S. Fish and Wildlife Service, Falls Church, Virginia.
HPWRA (Hawaii-Pacific Weed Risk Assessment). 2018. www.hpwra.org [accessed 18 October 2018].
GISD (Global Invasive Species Database). 2018. http://www.iucngisd.org/gisd/search.php [accessed 18 October 2018].
IUCN (International Union for Conservation of Nature). 2018. Version 2018-1. The IUCN Red List of Threatened Species™. http://www.iucnredlist.org/search [accessed 18 October 2018].
GISD (Global Invasive Species Database) 2018. Downloaded from http://www.iucngisd.org/gisd/search.php on 13 October 2018.
Lückhoff CA. 1933. Hoodiopsis triebneri. South African Gardening and Country Life 23.
Rowley, G. (1982). Intergeneric Hybrids in Succulents (Conclusion). The National Cactus and Succulent Journal, 37(3), 76-80. http://www.jstor.org/stable/42790705 [accessed 17 October 2018].
SANBI (South African National Biodiversity Institute) 2018. Keys to flora of southern Africa. Apocynaceae – Asclepiadoideae – Ceropegieae – X Hoodiopsis C.A.Lückh. http://biodiversityadvisor.sanbi.org/wp-content/themes/bst/keys/e-Key-20160604/Genera/G_HoodiopsisX.html [accessed 17 October 2018].
Page last updated 18 October 2018