Tylecodon ectypus
Tylecodon ectypus F.Gren. & Van Jaarsv.
Family: Crassulaceae
Common names: Steinkopf tylecodon (Eng.); Steinkopf krimpsiektebossie (Afr.)
Introduction
A recently described, rare, dwarf, succulent geophyte from the Richtersveld, Northern Cape. Plants are solitary or in small clusters, with a sparingly leaved, basal rosette in winter and a candelabriform inflorescence of pink, upward-pointing tubular flowers in summer, when the leaves die back.
Fig. 1. Illustration of Tylecodon ectypus by Marieta Visagie.
Description
Description
Tylecodon ectypus is a summer-deciduous, tuberous-rooted plant, usually solitary but sometimes sparingly branched, to about 100 mm tall (excluding the inflorescence). Roots tuberous, the tuber growing below the soil, sometimes rounded, squeezed in rock crevices and cliffs. The tuber is about 35–140 mm long and 20–40 mm in diameter, covered with flaking, greyish bark. The branches are succulent, short, ascending spreading, up to 100 mm long but most often no longer than 15 mm, 3–8 mm in diameter and rarely branched. The branches are covered with few truncate, light purplish phyllopodia, 2 mm long. The leaves are softly succulent, 2 to 3 per branch, variable in shape, 35–120 × 28–75 mm, channeled on the upper surface, with a short indistinct petiole 10–15 mm long. The leaf blade is broadly obovate to rounded, often concave, the base channelled and wedge-shaped (cuneate), gradually merging with petiole. The skin or epidermis is covered in short, 0.2–0.3 mm long, see-through (translucent), glandular hairs. The upper surface of the leaf is flat to concave, green to dull green, sometimes with purple margins, becoming orange to purplish at the end of the growing season. Both leaf surfaces are covered in thick veining, mostly on the upper surface, and without a distinct midrib. The leaf margin is entire, and the leaf tip is blunt (obtuse) to rounded. The inflorescence is sparingly branched, candelabriform, ascending, 80–220 mm long, bearing 1 to 3 apical groups of flowers (monochasia), each bearing 2 to 3 flowers. The peduncle is slender, wiry, erect, dark-brown, about 1 mm in diameter or less, covered in 4 to 13 spirally arranged bracts 10–14 mm apart, sparingly covered in glandular hairs (trichomes). The flower stalks (pedicels) are green, slender, 0.5 mm in diameter, 10–20 mm long. The buds densely covered in glandular hairs. The calyces maroon greenish, persistent and loosely attached, with glandular hairs. The calyx lobes are triangular, elongate, 4.5 × 1.2 mm. The flowers ascending, white with dark pink striations. The surface of the corolla is also glandular hairy, the tube trumpet-shaped and slightly bulging at the base, 4mm wide, widening gradually to 4.5 mm at the apex but swollen below the lobes. The lobes 5–7 × 2–2.5 mm, the upper surface whitish, with a dark pink stripe at the centre, the lower surface white with a central pink stripe, the margins and tips acute, but the tips are recurved during the day. The stamens 7–8 mm long, attached to the corolla throat, not protruding, anthers 1 mm long, squamae transversely oblong, 0.3 mm high and 0.7 mm broad, emarginate, translucent. The female portion 7 mm long the 5 carpels free, about 4 mm long tapering into styles 3 mm long, not protruding. Seeds not seen. Flowering time is in midsummer (January and beginning of February).
Fig. 2. Tylecodon ectypus in habitat on cliffs southwest of Steinkopf.
Conservation Status
Status
Rare but not threatened. Parts of its distribution fall within a reserve and are well protected.
Distribution and habitat
Distribution description
Tylecodon ectypus is only known from a few populations near Steinkopf in the Northern Cape, growing in a deep kloof. Although locally abundant, plants are always confined to the south-west facing slopes and sandstone cliffs. While they mostly grow in the shaded cracks of sandstone cliffs, they are also found on broader ledges on rocky soil supported by a moss and lichen crust. The south-west facing cliffs where Tylecodon ectypus grows are cooler, with shady winter conditions retaining additional moisture. Tylecodon ectypus grows around 800–1 000 m in altitude, in slightly acidic soil. It grows scattered in crevices and rock ledges. The rainfall occurs mainly during winter and it ranges from ± 150–250 mm per annum, with occasional fog. Summer temperatures are high during the day, the average is 30ºC, but with cooler nights. Winters are cooler and frost very rare.
Fig. 3. The habitat of Tylecodon ectypus, a deep gorge where plants grow on the more shady southern rock face, Skaaprivierspoort, west of Besondermeid, Northern Cape.
The vegetation in the habitat of Tylecodon ectypus consists Succulent Karoo. More precisely it has been classified as Namaqualand Shale Shrubland, Namaqualand Hardeveld Bioregion (Mucina et al. 2006). This dry river kloof where our species grows, is rich in species of Tylecodon. Downstream to Tylecodon ectypus it includes T. atropurpureus, T. tribblei, T. petrophilus, T. reticulatus, T. paniculatus, T. tuberosus, T. wallichii and T. pearsonii.
Derivation of name and historical aspects
History
Tylecodon ectypus started off as a mystery plant of which the origin was unknown. The plant appeared as a photograph on the internet in 2015, which immediately attracted attention because of its distinctness. The hairy leaves (up to 3) were rounded with thick veins on the upper surface, which reminded of T. singularis, a species that is only known from dolomite formations on the Hunsberg in southern Namibia. The new plant’s floral features however were very different to those found in T. singularis. The inflorescence and flowers were much smaller and clearly showed traits of belonging to a group of tuberous rooted species in Namaqualand. Clearly it was new and nothing was known of its origin. Before a species can be named, live plants or herbarium specimens must be studied from a known location.
It was only later, when plants were confiscated from a couple with a succulent nursery who were collecting plants in the Steinkopf district of Namaqualand, and ended up at the Karoo National Botanical Garden in Worcester, that the mystery became clearer, but still no one knew where the plant grew in the Steinkopf district.
Young, intrepid ecology student, Florent Grenier, while studying the pollination ecology of Pelargonium and various species in the Iridaceae, rediscovered this species on cliffs in the upper reaches of a deep gorge south of Steinkopf. He subsequently accompanied the author to the site, where the plant was studied and photographed in habitat. The author later revisited the site whilst the plants were in flower. Flowering material was provided to botanical artist, Marieta Visagie, who completed the illustration (see Fig. 1). The species was then jointly written up for Haseltonia, yearbook of the Cactus and Succulent Society of America, in 2020 (Van Jaarsveld & Grenier 2020).
The specific epithet ectypus, meaning ‘embossed’ or ‘in relief’, pertains to its leaves which have a metallic appearance especially the orange copper tints in late spring. In 1925, N.E. Brown described Conophytum ectypus which has a similar decorative leaf texture and also occurs in the same region.
Fig. 4. Tylecodon ectypus in a ceramic container in cultivation at Babylonstoren Farm in late spring, note the bulging veins and change in leaf colour.
Tylecodon ectypus has several features which are unique: the candelabriform branching of the inflorescence and the U-shaped inflorescence branches. Tylecodon ectypus is most closely related to Tylecodon atropurpureus, also growing in the same region but with large, elongated tubers, different leaves, different inflorescence and dark purple flowers (Van Jaarsveld & Koutnik).
Tylecodon is a genus of about 50 species. Prior to 1978, all species of Tylecodon were treated as belonging in the genus Cotyledon, a group of succulents widespread in Africa (Toelken 1978). Helmut Toelken, from the University of Cape Town, erected the genus Tylecodon for all the species with leaves which are spirally arranged, with a winter growing season that become deciduous towards the summer when they flower (Toelken 1978). The flowers of Tylecodon are also smaller than those of Cotyledon and most are pollinated by insects. Tylecodon is an anagram of Cotyledon. Presently there are more or less 50 named Tylecodon species occurring mainly in South Africa and southwestern Namibia. They are very variable in growth form, from large thickset shrubs like the Tylecodon paniculatus (botterboom) to about 2.5 m tall, to tiny geophytes such as T. occultans, T. schaeferianus and T. similis, only a few centimetres high. A few species are scandent shrubs from a tuberous rootstock, such as T. kritzingeri, T. tribblii and T. scandens. Cotyledon is easily distinguished by being evergreen, with leaves arranged in opposite pairs and large, colourful, bell-shaped flowers that are pollinated by birds, the best known being C. orbiculata.
Ecology
Ecology
Tylecodon ectypus escapes predation by its inaccessible, cliff-face habitat. Also, the tubers are deeply embedded in rock crevices and if the leaves are eaten the plant will simply re-sprout. The large tuber assists with storing moisture and nutrients, allowing the plant to flower during the long, dry summers when its leaves become deciduous.
Fig. 5. Tylecodon ectypus in bud, in its habitat, in late November, the leaves are dry and the ascending inflorescence is becoming visible.
The slightly concave, hairy leaves and channelled, short petioles assist with moisture trapping. The region is subject to periods of fog and receives dew in the mornings.
Fig. 6. A close up of a leaf of Tylecodon ectypus in habitat in winter, note the dried candelabriform inflorescence from the previous season, the slight concave shape, large distinct veins and marginal hairs assisting in trapping moisture from fog.
Uses
Use
No medicinal or cultural uses have been recorded.
Fig. 7. Tylecodon ectypus in early winter, note the slightly concave leaves.
Growing Tylecodon ectypus
Grow
Tylecodon ectypus is best grown as a pot plant in regions outside of its natural habitat. It grows best in dappled shade. Plants should be planted in a sandy gravely soil. Keep dry from late spring to autumn. Water the plants during late autumn and winter. They rapidly respond by producing leaves in its winter growing season. Fertilize plants with an organic fertiliser during winter and spring.
Fig. 8. Tylecodon ectypus in cultivation at Babylonstoren Farm, growing in a ceramic container during winter (left) and in late spring (right).
In regions outside of its habitat, ceramic containers are the solution. At Babylonstoren Farm plants are grown in a mixture of 2 parts sand or gravel, 1 part loam and 1 part compost. Keep in dappled shade. Avoid over watering.
Sow seed in in late summer or autumn, in a shallow tray, filled with a sandy mixture and keep moist. Germination is usually within 3 weeks and once large enough to handle, transfer to individual containers. Place container in a shady position but with full light.
Plants are relatively pest free, but wine weevils, slugs and snails can be a problem.
References
- Mucina, L. & Rutherford, M.C. (eds) 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria.
- Mucina, L., Rutherford, M.C. & Powrie, L. 2005. Vegetation Map of South Africa, Lesotho and Swaziland, 1:1 000 000 scale sheet maps. South Africa National Biodiversity Institute, Pretoria.
- Tölken, H.R. 1985. Crassulaceae. In: O.A. Leistner (ed). Flora of southern Africa 14(1):1-244. Botanical Research Institute, Pretoria.
- Tölken, H.R. 1978. New taxa and new combinations in Cotyledon and allied genera. Bothalia 12(3): 377–393.
- Van Jaarsveld, E. J. & Grenier, F. 2020. Tylecodon ectypus, a new cliff dwelling species from the Skaaprivier, northern Namaqualand (Northern Cape Province), South Africa. Haseltonia 27: 1–6.
- Van Jaarsveld, E. & Koutnik, D. 2004. Cotyledon and Tylecodon. Umdaus Press, Hatfield, Pretoria.
Credits
Ernst van Jaarsveld
Kirstenbosch National Botanical Garden (Retired 2015)
Babylonstoren Farm
Extraordinary senior lecturer and researcher,
Department of Biodiversity and Conservation, University of the Western Cape
January 2023
Acknowledgements: the author thanks Marieta Visagie for the illustration, Florent Grenier and his team for assistance in the field, and Babylonstoren Farm for allowing the study of the plants in habitat.
Plant Attributes:
Plant Type: Succulent
SA Distribution: Northern Cape
Soil type: Sandy
Flowering season: Late Summer
PH: Acid
Flower colour: Green, White, Pink
Aspect: Shade, Morning Sun (Semi Shade)
Gardening skill: Challenging
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