General Info – summary

This attractive willow-like Tree is up to 15m+ high and has a trunk diameter up to 0,6m.  Knob-like bulges may be present.  The simple, stipule lacking Leaves have a variable shape and occasional a red one. Bisexual, regular, 4-merous Flowers are in short spikes.  Each flower has 8 exserted stamens with white filaments and an inferior ovary with an exserted green style.  One seed develops in the 4-winged Fruit.

Description

Combretum erythrophyllum

Previous Names: Combretum erythrophylla, Combretum galpinii, Combretum glomeruliflorum, Combretum lydenburgiarum, Combretum riparium, Terminalia erythrophylla.

SA Tree No. 536.

Common names: (Afr) Geelhout, Riviervaderlandswilg, Riviervaderlandswilgerboom, Rooiblaar, Rooiblad, Rooibos, Vaalhanswilg, Vaalhanswilgerboom, Vaderlandswilg, Vaderlandswilgerboom.  (Eng) Bush Willow, Bushveld Willow, River Combretum, River Bushwillow, River Combretum, Vaal River Yellowood.  (IsiNdebele) Umdubu.  (isiXhosa) Umdubu.  (isiZulu) Umbondwe, Umdubu, Umdubu-wehlandze. Umdubu-wehlanze, Umhlalavane.  (Northern Sotho) Moduba–noka, Modibo.  (Setswana) Imbondvo-lemhlophe, Miavana, Modu, Modubunoka, Modubo.  (Tshivenda) Mugavhi, Mugwiti, Muvuvhu.

Family: Combretaceae (Bushwlillow family).  In this family, there are about 16 genera, which contain about 530 species.  In South Africa, there are 5 genera and 41 species.  Genera with Trees on this website include Combretum, Lumnitzera, Pteleopsis and Terminalia.  The simple and usually entire Leaves lack stipules.  Flowers are usually bisexual.  There are usually twice the number of stamens as sepals or petals.  The inferior Ovary has 1 locule and usually only 1 of the ovules develops into a seed.  Fruit is usually indehiscent and may be winged or ridged.

Name derivation: Combretum – climbing plants.  erythrophyllum – with red leaf – referring to the occasional leaf which is red.

Conservation: National Status: L C. (Least Concern).  Assessment: Raimondo et al. (2009).

Tree

This partially willow-like (branches tend to droop slightly) densely foliaged, medium sized Tree is up to 15m(+) high (photo 233).  The single Trunk is straight, and may reach a diameter 0,6m.  If “straight”, the main trunk may lean over (photo 231).  The plant may also be multi-stemmed from the base.  The trunk may have knob-like bulges that are not galls (photo 488).  The tree has a sparse or large spreading Crown (photo 233).  Here the pale Bark is usually grey, smoothish and flakes with age to expose paler grey patches, which create a mottled appearance.  Young stems may be hairy, and usually branches develop low down (photo 233).

Leaves

This deciduous tree has slightly wavy Leaves that are opposite, 3-whorled or sometimes alternate.  All 3 may occur on the same tree.  New soft, hairy leaves may be a light delicate green whereas mature leaves become somewhat leathery, slightly darker, glossy and densely packed (photo 740).  Leaf shape (photo 230) is elliptic to lanceolate to oblong or oval, and leaves are up to 10 x 4cm.  All leaves are more than twice as long as wide and simple (have a single blade which may have incisions that are not deep enough to divide the leaf into leaflets).  Young leaves are viscous (having a thick, sticky consistency between solid and liquid).  If the temperatures are below zero in autumn, leaves may turn bright red to purple.  Some leaves turn yellow or red at any time of the year (photo 758) – hence the name erythrophyllum (with a red leaf).  The upper surface is slighter darker, and yellowish green below.  On the upper surface, the Midrib (which may be red) and lateral Veins are sunken, whereas on the lower surface the 6-10 pairs of conspicuous lateral veins protrude, are yellowish green, raised and curve towards the apex (photo 230).  The veins are lightly hairy above and hairier below.  On the lower surface, in leaf axils, hairy Domatia (a tiny chamber produced by plants that house arthropods.  To the naked eye, the domatia may appear as small bumps) may occur.  They are intended to be used by organisms that have a symbiotic relationship with the plant).  Secondary vein details are more clearly visible if the leaf is held against a strong light (photo 743).  Marginal hairs are visible on this photo.  The untoothed leaf Margins are finely fringed, entire (with a continuous margin, not in any way indented – photo 230) and not rolled ender.  The Apex tapers to a point-like tip and the Base is rounded or tapers.  The short Petiole (leaf stalk – photo 230) is up to 4mm long and fringed with hair.  Stipules (basal appendages of the petiole) are absent.  Before they fall, the leaves may turn yellow or reddish (photo 740).

Flowers

The sweetly scented Flowers usually emerge after the new leaves and develop in clusters or Spikes (simple indeterminate inflorescence with sessile flowers on a single unbranched axis opening in succession towards the apex).  The up to 20cm long spike (photo 260) shows the oldest developing hairy green fruit at the base and the younger flower at the apex.  The cream to light yellow, bisexual Flowers are actinomorphic (Regular, symmetrical.  Flowers are vertically divisible into similar halves by more than 1 plane passing through the axis).  Each small flower is about 1cm in diameter and 1,5cm long (photo 260) and the hairy Peduncle (stalk of flower cluster – photo 260) is bracteate (bract – a much-reduced specialised leaf, particularly the small scale like leaves in a flower cluster or associated with flowers).

Individual flowers have a small greeny Calyx with 4 Sepals, which forms an extension above the ovary (photos below).  The very short Petals are hairless and obovate to elliptic.  The 8 Stamens are in 2 whorls (unlike Combretum bracteosum which has 10 stamens).  The initially white Filaments extend the medifixed (attached by the middle) Anthers beyond the calyx and corolla.  The single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma) has a completely inferior Ovary (situated below the calyx).  N.B. this can be mistaken for the absent pedicle (flower stalk).  The ovary has 1 Locule in which only 1 of the 2 ovules develops.  The free greenish-yellow Style (photo 260) is wider than the filaments and extends the Stigma slightly beyond the white stamen

Fruit

The almost spherical indehiscent Fruit is initially pale green, hairy and ellipsoidal (photo 908).  In this photo, the remains of the stigmas and stamens are still visible.  The fruit becomes light brown (or honey coloured) 4-winged, up to 1,5 x 1,2 cm (photo 288) with wings up to 6mm wide, and usually has a well-developed, apical peg (photo 29).  The fruit becomes light brown and hairless when mature.  The old fruit may remain on the tree (photo 285) until the following spring – even after the new flowers appear.  Each fruit contains a single viable Seed.  (Jan-Oct).

Distribution & Ecology

This tree is a southern Africa endemic. (Endemic: restricted to a particular geographic location).  Trees occur from Eastern Cape, KwaZulu-Natal, and Northern Cape (along the Orange River), Mpumalanga, Free State, Gauteng, Limpopo, and North West (along the Gariep River).  They also occur in Eswatini (Swaziland), southern Mozambique, Eastern Botswana, Zimbabwe and Zambia.  The drought resistant Trees usually grow along streams or in moist ground – even in the Highveld up to an altitude of about 1 700m enabling the plant to exist in a wide habitat range.  Thick stands can develop close to rivers.  Here they may hang over the moving water.  They occur in the bushveld and savannah (a rolling grassland scattered with shrubs and isolated trees, which can be found between a tropical rainforest and desert biome).  Pied Barbets, Giraffe, Elephant, Bushbuck and Nyala consume various parts.  Wasps may lay their eggs in the fruit and hatched larvae feed on the seeds.  They in turn attract birds like the Southern Black Tit (Melaniparus niger) which open the hard fruit and consume the larvae.  These birds (blue-black males and greyish females) prefer broad-leafed woodlands and are especially common in Western Zimbabwe.  Pied Barbets (Tricholaema leucomelas) with their black and white striped heads may consume the Fruit.  This tree has been planted in the USA as a shade and ornamental tree.

Ethnobotany

The yellowish and featureless Wood is soft, tough and shows little distinction between sapwood and heart wood (photo 302).  It is easy to work and used as a general-purpose timber.  Wood is subject to borer attack and should be cut when the sap is low, and then water seasoned.  Rafters, furniture and cattle troughs are made from the wood.  A non-cracking Gum is extractable from cut stems.  This gum can produce a good, non-cracking varnish – used to mend cracks in pottery.  Root extracts are used in rich dark brown dyeing, and for tanning.  Roots are not likely to lift paving and, together with stems, are used in local medicine.  Dried Fruits make an attractive addition to flower arrangements.  Consider the Seeds poisonous to man.  The tree is drought and frost resistant and plants do well in gardens – providing both shade and attractive seeds.  Seeds take under 2 weeks to germinate.  This is fast growing ornamental tree is also grown in the United States.  It should grow 1 metre or more per year.  However, it needs protection against frost during the first 2 years.

References

Boon, R. 2010. Pooley’s Trees of eastern South Africa. Flora and Fauna Publications Trust, Durban.

Burrows, J.E., Burrows, S.M., Lotter, M.C. & Schmidt, E. 2018. Trees and Shrubs Mozambique.  Publishing Print Matters (Pty) Ltd.  Noordhoek, Cape Town.

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

Foden, W. & Potter, L. 2005. Combretum erythrophyllum (Burch.) Sond. National Assessment: Red List of South African Plants version . Accessed on 2024/09/14.

Ginn P.J. Mcilleron W.G. and Milstein P. le S, 1989. The Complete Book of Southern African Birds. 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. Jacana, Johannesburg.

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

 

http://witkoppenwildflower.co.za/combretum-erythrophyllum/

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

http://plantzafrica.com/plantcd/combreteryth.htm

http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=141910

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