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Accepted Scientific Name: Tylecodon rubrovenosus (Dinter) Toelken
Bothalia 12: 380 1978.
Origin and Habitat: South Namibia and Republic of South Africa (Northern Cape) on both sides of the lower Orange River from the mouth to near Prieska.
Type locality: South West Africa/Namibia, south of Warmbad.
Habitat and ecology: Succulent and Nama Karoo. Tylecodon rubrovenosus usually grows on exposed rocky slopes of hills and mountains in the Orange river region. It is rare but not threatened.
AFRIKAANS (Afrikaans): knoppiesnenta
Description: Tylecodon rubrovenosus (Cotyledon rubrovenosa) is a sparingly branched ascending, perennial, succulent shrub to 30-35 cm tall, with solitary main stem, the short, thick branches are covered with phyllopodia (Expanded and hardened tubercle-like leaf-bases) which later disappear with the peeling bark.
Derivation of specific name: The specific epithet “rubrovenosus” comes from the Latin 'ruber, rubra, rubrum', meaning red; and from the Latin 'Venosus', meaning veined; for the reddish striations on the leaves.
Stems: Branches grey-green, about 2 cm in diameter (to 4 cm across at the base), occasionally becoming thicker upwards, with short irregularly shaped phyllopodia to 1 mm tall but later replaced by a peeling, grey-brown.
Leaves: Crowded at branches tips, linear to linear-lanceolate, (10-)25-40(-80) mm long, 2-4(-6) mm wide, ascending, curved inwards, terete, slightly cuneate, glandular-hairy to glabrous, upper (dorsal) face often slightly grooved, lower (ventral) face convex, acute, glandular-pubescent to glabrescent when young and becoming glabrous later (but the plants west of the coastal mountains tend to remain glandular-tomentose), greyish-green, often with conspicuous reddish striations.
Inflorescences: The inflorescences are spreading thyrses up to 20(-37) cm tall with 20 or more nodding yellowish-green flowers. The peduncle is 60-120 mm long, pale yellow, with 3-7 straight monochasia (branches), but which usually zig-zag when young, each with 4-9 flowers. Pedicels 3-6 mm long. All the parts of the inflorescence are glandular-pubescent.
Flowers: Pendulous. Calyx 4-6 mm long, glandular-tomentose, yellowish green. Sepals 6-7 mm long lanceolate-triangular, the apex acute to obtuse. Corolla yellowish green, tubular, 7-15 mm long, yellowish-green, glandular-pubescent, lobes spreading to recurved. Tube cylindrical to funnel-shaped, 7-9 mm long, glabrous inside except for few hairs where filaments are fused to tube. Corolla lobes 5-7 mm long, draw back. Anthers 1,5-1,8 mm long. Squamae oblong to square, 0,8-1,2 long, 0,5-1 mm wide, fleshy, yellowish orange.
Blooming season: This specie flowers in spring and early summer. September, October (November).
Bibliography: Major references and further lectures
1) Urs Eggli “Illustrated Handbook of Succulent Plants: Crassulaceae” Springer Science & Business Media, 06 December 2012
2) J.P. Roux “Flora of Southern Africa” 2003 retrieved from http://plants.jstor.org/stable/10.5555/al.ap.flora.flosa003230383800031?searchUri=filter%3Dname%26so%3Dps_group_by_genus_species%2Basc%26Query%3DTylecodon%2Brubrovenosus
3) Doreen Court “Succulent Flora of Southern Africa” CRC Press, 01 June 2000
4) Ernst Van Jaarsveld, Ben-Erik Van Wyk, Gideon Smith “Succulents of South Africa: A Guide to the Regional Diversity” Tafelberg, 2000
5) Urs Eggli, Leonard E. Newton “Etymological Dictionary of Succulent Plant Names” Springer Science & Business Media, 29 June 2013
6) all, A.V., De Winter, M., De Winter, B. and Van Oosterhout, S.A.M. 1980. “Threatened plants of southern Africa.” South African National Scienctific Programmes Report 45. CSIR, Pretoria.
7) Hilton-Taylor, C. 1996. “Red data list of southern African plants.” Strelitzia 4. South African National Botanical Institute, Pretoria.
8) Raimondo, D., von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. and Manyama, P.A. 2009. “Red List of South African Plants.” Strelitzia 25. South African National Biodiversity Institute, Pretoria.
9) Tölken, H.R. 1985. Crassulaceae. In: O.A. Leistner (ed). “Flora of southern Africa” 14,1:1-244. Botanical Research Institute, Pretoria.
10) van Jaarsveld, E.J. & Victor, J.E. 2007. Tylecodon rubrovenosus (Dinter) Toelken. “National Assessment: Red List of South African Plants” version 2017.1. Accessed on 2017/04/17
Cultivation and Propagation: Although usually grown only by specialist caudiform grower it presents no great difficulty in cultivation. It is a winter grower, dormant in the summer.
Growing rate: This is a very slow growing species.
Soil: Tylecodon rubrovenosus, like all other caudiciforms, requires very well-drained soils. Out-of-Doors prefers sandy soil, sandy loam soil provided the drainage is good. In pot it needs an open medium comprising equal parts of well decomposed compost or finely milled bark, and river or silica sand (or pumice) or a well drained, cactus compost.
Repotting: Re pot every 2/3 years using the above compost with added slow release fertilizer, but fully grown plants can remain in the same position for many years. Plant it with the neck at soil level and grow it in pots with a diameter of at least 25 cm. Give it excellent drainage.
Fertilization: Because they are adapted to poor soil, feeding is not really necessary, but some ash will not do them any harm. On pots fertilize moderately during the growing season with diluted high potassium fertilizer.
Exposure: It is most suitably grown in full exposed areas but it will even grow and bloom in half-sun.
Watering: As it is a deciduous winter-growing plant, it likes moisture from late summer to early spring, and withhold water from late spring to summer (dormancy period). In the growing season water when the roots are almost dry, and reduce watering in winter to once every two weeks.
Hardiness: Winter minimum temperature is 5ºC but better at 8ºC. The leaves easily drop off in cool conditions.
Garden uses: The plants are mostly grown by specialist caudiciform collectors, usually as container subjects.
Warning: The plant is poisonous to stock, causing stomach cramps.
Pest and diseases: It is susceptible to attack by mealy bugs.
Propagation: From seed. Seeds form readily and should be harvested and sown as soon as they can be easily removed from the capsules. The seeds germinate without difficulty. Seeds may take up to two months before the first leaf appears above ground, and a further 10 to 20 years to reach maturity. If it is the intention to plant these seedlings out into a bag or pot, they can be transplanted in their second or third year. Once planted in a permanent position do not dug-up and moved them constantly from one location to the next. A word of caution - do not plant the swollen stems too deep. Ensure the slender neck of the plant is just protruding above the soil with only the root underground. It can also be propagated from cuttings in late Autumn.
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