Tavaresia barklyi (T.-Dyer) N.E. Br.
Common names: Devil's trumpet (E); bergghaap, katstert (A); olukatai (Ndonga, Ovamboland, northern Namibia); okukato lekadi, olukato lendume (Kwanyama, Ovamboland, northern Namibia)
The neat appearance of the ribbed stems furnished with bristles at first reminds one of a cactus, but when the bizarre trumpet-shaped flowers appear, one realizes that it is not. These large, trumpet (tubular) flowers are characteristic of the genus while the many-ribbed stems are characteristic of the species.
Tavaresia barklyi is as succulent herb with cylindrical, 10-12 ribbed, blue-green stems. The large and showy flowers arising from the base of the stems are tubular to trumpet-shaped and range from 35-100 mm long and ± 25 mm in diameter. One to four flowers per inflorescence open successively.
The flowers are pale yellow to cream to flesh-coloured with dark red spots and streaks on the outside, darker on the inside becoming almost fully maroon to purple at the base inside.
The stems are erect, 40-60 mm long and ± 15 mm in diameter, many angled and covered by tubercles that are tipped by three sharp bristles. It is reported that when the stem is injured or crushed it emits a strange musty odour.
The fruit consists of elongated follicles which house the seeds. When the follicles are fully-mature, they burst open to release the seeds, each of which has a tuft of hair.
Although this species has a wide distribution range, it is rarely abundant. According to the latest assessment, the bergghaap is listed as of Least Concern in South Africa (2009) and not listed in the Red Data Book of Namibian Plants (2005). It is, however, protected under the Limpopo Environmental Management Act 2003 in the Limpopo Province (South Africa)
Distribution and habitat
Tavaresia barklyi is widely distributed in southern Africa and reported for Angola, Botswana, South Africa (Free State, Limpopo and Northern Cape Provinces), Namibia and Zimbabwe. Plants grow in full sun or light shade on rocky outcrops and slopes and in sandy soils on plains, usually in somewhat protected situations.
Derivation of name and historical aspects
The genus currently consists of three species: T. barklyi, T. angolensis and T. thompsoniorum distributed in southern and tropical Africa.
Tavaresia hybridises easily and a hybrid between T. barklyi and Stapelia gigantea has been described as T. meintjiesii. Some taxonomists are of the opinion that T. thompsoniorum may also be of hybrid origin.
In the genus the outer corona consists of lobes that are basally fused becoming threadlike and ending at the tips in a spherical knob.
T. angolensis and T. barklyi are distinguished by the ribbing on their stems; the former species has from five to nine ribs and the latter, eight to fourteen. These two species are in turn distinguished from T. thompsoniorum by the size of the tube, shape of the lobes and colouring of the flowers.
The genus was established in 1854 by Welwitsch, an Austrian botanist, based on plants collected from Angola. He dedicated the genus to Josè Tavares de Maçedo, an official in the Portuguese ministry of Marine and the Colonies. The specific epithet honours Sir Henry Barkly (1815-1898) who was Governor of the Cape in 1870-1877 and who collected specimens in 1871.
At one stage the species was placed in the genus Decabelone which literally means ten prickles. It was later found that the species from Angola had priority under the ICBN (International Code of Botanical Nomenclature) and the generic name Tavaresia was re-introduced by N.E. Brown in Flora Capensis in 1909. When two taxa (the same species) are described validly by different people (usually in different publications) the older of the names is accepted according to the rules of the ICBN which is why the name Tavaresia is used instead of Decabelone. The interesting history of the usage of the generic name Tavaresia versus Decabelone is fully discussed by Leach (1993).
The long tubular flowers immediately distinguish this species from any other known stapeliad in southern Africa.
The plants bloom in midsummer (November to April), usually after rain. The tubular flowers and intricate fertile parts indicate a plant adapted to specific pollinators. Plants are insect pollinated and thus far, to my knowledge, the specific pollinators have not been recorded. An interesting topic for further research would be to determine whether the large-and-small-flowered forms are pollinated by different insects as two forms were formally known as two distinct species (T. barklyi and T. grandiflora).
The seed are released from the fruit when they split open. As the tuft of hair (coma) dries out on the tip of the seed it unfolds into a parachute-like structure that carries the seed off in the slightest breeze. The distribution of the seeds by wind probably explains the wide spatial distribution of plants in a community. After a time the coma detaches and, if the seed lands in a suitable place, it will germinate and establish a new plant.
The bergghaap is mainly grown by plant collectors, lovers of succulents, and enthusiasts who enjoy growing unorthodox looking plants.
Except for its horticultural use, not much is known about other uses. It has been reported that the plant is crushed and externally applied to painful and aching parts of the body as a kind of dressing to alleviate pain.
It has also been reported that the stems are chewed, possibly for nourishment or to obtain fluids. The outer skin of the stems is peeled and it is then in the same way as Hoodia is widely used. It has not been established whether Tavaresia acts as an appetite suppressant.
Growing Tavaresia barklyi
Growing this fascinating species may be a challenge for the collector.
Tavaresia may be a good indigenous substitute for any exotic cactus that is grown in a container on a veranda or window sill. It is interesting even when not in flower.
The species grows naturally in situations of light shade. It prefers sandy soils and high temperatures and grows in areas that receive summer rainfall, never in areas that are prone to frost and low winter temperatures. It is well suited for cultivation in the north and north-western provinces of South Africa. In areas that have mild winters and receive infrequent frost it may do well as a container or indoor plant. Success in growing the plant could be achieved if the natural growing conditions are successfully simulated.
The devil's trumpet can be cultivated reasonably easily if kept relatively dry in cold and wet conditions. When rot does occur, it is advised to graft the healthy parts onto any strongly -rooted Stapelia. Tavaresia are easily propagated by stem cuttings or seed.
Tavaresia is easily grown from fresh seed but less easy to keep plants healthy. Seeds take about a year to ripen but germinate rapidly after sowing (the fresher the seeds the better). Seed should be sown in spring in well-drained, light, sandy soil mixed with compost and covered with a thin layer of soil. The pH should be 6.5-7.5. Plants need to be kept in a shaded and fairly moist position and temperatures should be kept at 25-35°C.
Once the seedlings have germinated and are about 5 cm high they can be pricked out and planted (be careful not to damage the roots when pricking out!). Th plants generally grow quickly and most will flower within two to three years when grown from seed.
Cuttings should be taken during the active growing stage to ensure good rooting, before the plants enter their dormant phase. Cuttings can flower in their first year depending on the size of the cutting. Travaresias grow easily from cuttings as long as they are given adequate time to dry out before planting (at least two weeks). Leave the cuttings in the shade to dry out. Use a fungicide drench before planting. Place them in a well-ventilated area with about 40% shade. Water daily during very hot weather. Plants that do not grow well from cuttings can be propagated by grafting. Keep plants well ventilated and in good light to prevent damping off. Feed once in the growing season (summer) with a fertilizer (Seagro or Bounceback). The soil should drain well: equal parts of washed river sand, potting soil and topsoil is recommended. It is important to keep the plants dry during the winter otherwise they rot easily. Plants prefer warm but dry atmospheres in well-drained soils. They grow in full sun or semi-shade and are totally frost-intolerant.
Plants are susceptible to black rot (bacterial infections) and seedlings to damping-off (Pythium infection). Treat the seedling medium with a fungicide but bear in mind that some chemicals may stunt their growth. The devil's trumpet is extremely susceptible to rot caused by woolly aphids infesting the roots. Woolly aphids on the roots and underground stems and mealy bugs on the stems and bases are the most common problems. A strong jet of water or a 50/50 mix of methylated spirits and water can be used to eradicate these pests. Black rot, a secondary infection after woolly aphid attacks, is also problematic. Remove all traces of black rot with a sterile knife, spray the plant with Benelate and dust with flowers of sulphur. The affected parts should be cut away and destroyed as soon as stem rot is noticed.
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Plant Type: Succulent
SA Distribution: Free State, Limpopo, Northern Cape
Soil type: Sandy
Flowering season: Late Summer, Autumn
Flower colour: Brown, Red, Cream
Aspect: Full Sun
Gardening skill: Average