Stoeberia carpii is one of six Stoeberia species endemic to the winter-rainfall region of South Africa and Namibia. They are shrubby leaf succulents, and S. carpii is at once recognized by its erect growth, large pale grey-green leaves (largest in the genus Stoeberia ), elongated flowering branches, large white flowers (largest in Stoeberia ) and seed which is not wind-dispersed.
Ascending, branched woody shrubs to 1,5 m tall with a single main stem up to 40 mm in diameter. The bark is greyish brown becoming grey and fissured longitudinally. The younger branches are succulent and terete (cylindric), about 5 mm in diameter, the internodes are 1090 mm apart.
Leaves are in opposite pairs, succulent, laterally compressed, ascending, sickle-shaped, oblong-club-shaped, grey-green, 5090 mm long and 1520 mm in diameter at the widest point. They are obscurely triangular in cross section with a blunt keel toward the end, and a small hard point (mucronate).The leaf pairs are fused at the base, forming a short sleeve down the stem.
Flowers are arranged in rounded terminal inflorescences on elongated branches spreading close to the ground and bearing up to 10 flowers 2035 mm in diameter. The sepals are triangular and 24 mm long. The petals (petaloid staminodes = petal-like sterile stamens) are white and about 10 mm long, linear, and spreading in open flower. The stamens and staminodes occur in a dense cone (yellow centre). Flowering time: winter to spring.
The fruiting capsule is 810 mm across, angular and funnel-shaped with 5 or 6 locules. The capsule remains open after initially opening. The seeds are pear-shaped, minutely warty, 0.80.9 mm long.
This plant has not been assessed yet formally. Stoeberia carpii is rarely seen in cultivation. It is also very rarely seen in the field and is known from only two locations adjacent the Orange River, the one in Namibia and the other in the Richtersveld National Park, South Africa. The locations in the Richtersveld at the Godas Beacon, where it was first located, have not been found again.
Distribution and habitat
Stoeberia carpii is confined to winter-rainfall Succulent Karoo (Northern Richtersveld Scorpion's tail veld) along the lower Orange River Valley, and is known only from two sites. The first at Lorelei, situated on the foothills of the Hunsberg near Rosch Pinah in Namibia, and the other near Kodas Peak in the adjacent Richtersveld National Park, South Africa. The author visited the habitat at Lorelei, on south-facing foothills in November 2006. Here the species is locally common, on rocky terrain (igneous rocks) with other plants such as Euphorbia hottentota, E. mauritanica, E. decussata, Schotia afra var. angustifolia, Aloe dichotoma and Zygophyllum prismatocarpum. Smaller associated species include Crassula rupestris subsp. marnieriana, C. herrei, Didelta carnosa, Cotyledon orbiculata and Commiphora capensis.
In the past, several sites were visited near Kodas Peak (in northern Richtersveld in Scorpion's tail veld) where S. carpii was once recorded, but no plants were observed.
Rain falls mainly during winter (May to September) and averages between 250 and 400 mm per annum. The summers are dry and very hot (up to 40°C on hot days). Winters are cooler but warm during the day and if frost occurs, it is very light and occurs over short periods only.
Derivation of name and historical aspects
Stoeberia carpii was first collected by Kurt Dinter at Kahanstal on 6 December 1934 in southern Nambia, and was named by H. Chr. Friedrich in the Mitteilungen der Botanischen Staatssammlung München 3: 563 (1960). The specific epithet commemorates Mr Bernard Carp, succulent plant collector from Houtbaai, Cape Town.
Stoeberia carpii grows on southern slopes of the lower Hunsberg and is not uncommon near the Lorelei Mine in the southern Hunsberg. It is usually confined to mountainous terrain and usually to southern aspects. It grows in scattered, small groups. It is a woody shrub bearing slender flowering branches which often become spreading and drooping, releasing their seed close to the mother plant, an example of what is termed autochory' or selfdispersal (Van Jaarsveld 1994). Although selfdispersed (autochorous), the seeds are released away from the mother plant by the long extended branches, which is termed blastochory (Van der Pijl 1982). This results in the offspring of the plant remaining in the present favourable habitat but some distance from the mother plant. Most mesembs have capsules which open when they become wet, and close again when becoming dry; thus they tend to conserve the seeds, rather than shedding them all at once. By contrast, the capsules of all Stoeberia species remain open once they have opened. All Stoeberia species, except S. carpii, are usually dispersed by wind (Van Jaarsveld 2006).
Uses and cultural aspects
No uses have been recorded for S. carpii , except as a collectors' item by succulent enthusiasts and botanical gardens..
Growing Stoeberia carpii
Stoeberia carpii does well in cultivation at Kirstenbosch and has been introduced to the Botanical Society conservatory where plants can be seen in the Namaqua Richtersveld bed. Here the plants have a life span of about 12 years. They grow fairly rapidly, and are best cultivated in winter-rainfall succulent karoo gardens (Van Jaarsveld 2010).
Stoeberia carpii also thrives as a container plant away from its succulent karoo habitat. In karoo regions and where the climate permits, it should thrive outdoors. The soil should consist of gravel and sand (with ample loam or clay added) and planted in full sun. Keep containers in a sunny situation, only water from autumn to spring and dry off during summer, or water sparingly. Containers should be well drained. Place a gravel layer at base of container. During the cool months a liquid organic fertilizer can occasionally be added. Plants can remain in the same container for a number of years. Pests include the caterpillar of the tiger moth. It is easily controlled by hand or by spraying or dusting with a contact poison.
Propagation. Plants grow easily from seed sown in a sandy mixture in a coarse gravel or sandy soil during late autumn. Cover with a thin layer of sand (12 mm thick) and keep moist and in a sunny situation. Germination is within 3 weeks and plants should be able to flower in the third year.
- Van Jaarsveld, E.J. 1994. A synopsis of the genus Stoeberia . Aloe 31, 3 & 4: 6876.
- Van Jaarsveld, E.J. 2006. Notes on Stoeberia and its allies. Aloe 43: 1822.
- Friedrich, H. C. 1960. Mesembryanthemum studies. Beiträge zur Kenntnis der Gattungen Stoeberia Dinter et Schwantes und Ruschianthemum Friedr. Gen. Nov . 3: 560563.
Ernst van Jaarsveld
Kirstenbosch National Botanical Gardens