General Info – summary

This Tree + its caustic latex may reach 7m high.  Young branches have paired spines.  Older branches are lost.  The Crown is mop shaped.  Mature Leaves absent.  Photosynthesis occurs in young stems.  Unisexual Flowers lack a perianth and are in cyathia.  The many male flowers are each reduced to a single stamen surrounding the single pistil.  Here the 1 trilocular, superior, ovary has 3 styles.  Fruit is a woody capsule.

 

Description

.

Euphorbia sekukuniensis

Previous Names: Nil.

SA Tree No. 353.

Common names: (Afr) Sekhukhuni-naboom, Sekoekoensnaboom.  (Eng) Sekhukhune Candelabra Tree, Sekhukhuni Euphorbia.

Family Euphorbiaceae (Euphorbias family e.g., the exotic poinsettia – Euphorbia pulcherrima).  This family has about 275 genera and 7 500 species with a very wide distribution.  In South Africa, there are 50 genera and 484 species.  Apart from Antarctica, members of this family are present in all continents.  This family has many herbs, and in the tropics, shrubs and trees, including succulents and climbers, are more common.  Local tree containing genera on this website include Croton, Euphorbia, and Spirostachys.  Leaves, when not rudimentary, are usually alternate, and simple.  Stipules are usually present as hairs, glands or spines.  Plants may be monoecious or dioecious.  Inflorescences are situated terminally or in leaf axils.  They are mostly in cymes (a broad, more or less flat-topped, determinate flower cluster, with central flowers opening first).  The unisexual flowers are monoecious or dioecious, and regular.  Colourful bracts may be present below the flowers.

Name derivation: Euphorbia – after Euphorbus: physician to the king of Mauretania (approximately 10 BC).  sekukuniensis – where plant was found (Sekhukhuneland) – named after the 19th century chief: Sekhukhune – paramount King of the Bapedi, from 1861 until his assassination on 1882.  R. Ross-Frames first collected this plant in 1930.  There are a large number Euphorbia species in southern Africa.

Conservation: National Status: Rare. Assessment Date: 2008.  (P.J.D. Winter, J.E. Victor and L. von Staden).  This plant is threatened by highly destructive open cast mining for platinum in calcium rich rocks.  None of the location areas lies within conservation areas.  Their existing environment is potentially threatened by this mining.

Tree

The usually single, stout and upright Tree (photo 632) may reach 7m high.   The tree ends in 4-5 angled (photo 450) branchlets that are up to 1m long and 2cm wide.  The branchlets have slight constrictions, at intervals of up to 20cm (photo 361 – under Fruit).  From here, they may branch again.  Collectively the branchlets make up the dense, candelabra or mop like Crown.  There is a continuous horny strip of united spine shields along each margin (photo 920).  These shields widen at each pair of spines and taper towards the one above.  The paired Spines may initially be red (photo 400).  They become grey, stout, rigid and up to 8mm long (photo 920).  The older, lower down, branchlets tend to droop prior to falling (photo 825).  When they fall, they leave behind up to 8 vertically arranged visible holes that remain there for some time (photo 821).  These are distinctive.  This loss of branchlet results in a branch-free Stem (photo 825).  The uniformly grey, smoothish Bark surrounding the holes is slightly raised (photo 821).  In the older, now dark grey bark, the holes are no longer visible.  Lichen (composite organism arising from a mutualistic relationship between fungi or cyanobacteria and algae species may be present on the stem – photo 628).

Flowers

The Flowers occur in an inflorescence called a Cyathium (name given to the cup-shaped inflorescence that appears as a single flower but is a collection of reduced flowers).  In this plant, the cyathia are horizontal on very short stalks.  They are yellow/green and occur near branchlet tips on the ridges – just above the 8mm long paired spines (photo 361 – under Fruit).  A perianth (sepals and petals) is absent.  Each cyathium is composed of unisexual flowers surrounded by bracts and often glands.  These flowers are monoecious (having both male and female reproductive organs on the same plant) but never on the same flower.  Thus, individual flowers are either male or female and are both found within an Involucre (one or more whorls of small leaves or bracts standing underneath a flower or flower-cluster).  Male flowers surround the single female flower.  Each Male Flowers is reduced to a single Stamen (photo 447).  N.B.  Here each visible stamen is of a complete male flower.  Here the longitudinally dehiscent Anther has 2 Thecae (pollen sacs).  The centrally positioned solitary Female Flower has a single Pistil with a single, 3-locular, superior Ovary and 3 persistent Styles (photo 451 still visible in the in the now developing Fruit).  Each locule has a single Ovule.  Both the surrounding coloured modified bracts and nectar glands attract insect Pollinators.  (Jul-Sep).

Fruit

At maturity, the red Fruit has 3 distinct Lobes (photo 639).  Here the remains of the single stamens are still visible.  The stalked fruit is a woody, 3-valved Capsule (a dry fruit resulting from the maturing of a compound ovary, which usually opens at maturity by one or more lines of dehiscence).  The capsule is red when mature and about 8mm wide.  In photo 361, the proximity of paired spines just below the aging inflorescence (with a few old stamens) are also visible.  (Sep-Dec).

Distribution & Ecology

This mostly grassland growing tree is found mainly in southern Limpopo and slightly over the boarder of Mpumalanga.  These plants are also common on noritic rocky outcrops (deeply developing intrusive igneous rocks) in the Leol0 Mountains – usually at an altitude of 900-1 389m.  These plants are also found in Savanna (a rolling grassland scattered with shrubs and isolated trees, which can be found between a tropical rainforest and desert biome).  The tree is endemic (restricted to a particular geographic location) in South Africa –specifically in Sekhukhuneland (between Mashishing – Lydenburg and Polokwane in Limpopo) and in the Steelpoort River Valley as far as the Olifants River (a tribute to the Limpopo River) Valley.  Inflorescences attract insects, including butterflies).

Ethnobotany

Caustic milky Latex is present.  This is very poisonous and can cause blistering, allergic reaction or even blindness.  Do not collect wood near this tree to use in a Braai.  Rince any body area that comes in contact with poisonous latex with substantial amounts of water.  Plants are succulent and cactus like but the true cactus, in the family Cactaceae, lacks both the paired spines and the poisonous latex.

References

Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of Southern Africa, edn 3. Struik, Cape Town.

Lawrence, G. H. M, 1951. Taxonomy of Vascular Plants. The Macmillan Company, New York. Tenth Printing 1965.

Palmer, E. & Pitman, N. 1972. Trees of southern Africa, Balkema, Amsterdam, Cape Town.

Schmidt, S. Lotter, M. & McCleland, W. 2002. Trees and Shrubs of Mpumalanga and the Kruger National Park.

van Wyk, B. & van Wyk, P. 1997 Field guide to Trees of Southern Africa, Struik, Cape Town.

Winter, P.J.D., Victor, J.E. & von Staden, L. 2008. Euphorbia sekukuniensis R.A.Dyer. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2023/05/29.

 

http://hpra-atom.wits.ac.za/atom-2.1.0/uploads/r/historical-papers-research-archive-library-university-of-witwatersrand/e/9/7/e97e0ad91d200dc3e46c14cb85f813730573c4c1a2c2520d37a27aa8bfe0c0c4/A1655-E9-01-jpeg.pdf

http://www.iucnredlist.org/details/30346/0

http://posa.sanbi.org/flora/browse.php?src=SP33

https://www.sahistory.org.za/people/king-sekhukhune

https://en.wikipedia.org/wiki/Cactus