General Info

Tree up to 12+m high. Bright green, simple spring Leaves are 3-veined from the base. Small, wind pollinated, monoecious Flowers lack petals and occur with the new leaves. Fruit: small, fleshy ovoid Drupe.

Description

Tree

Celtis africana, Celtis rhamnifolia, Celtis kraussiana, Celtis burmannii, Celtis eriantha.

RSA Tree No. 39.

Common names: White Stinkwood, African White-stinkwood, Camdeboo stinkwood, witstinkhout. Freshly cut wood may smell hence the name white stinkwood.

Family: Cannabaceae: (white stinkwood family). The family includes approximately 11 genera including Cannabis (an erect herb),  Humulus (hops: climbing plant). Genera with trees include Celtis and Trema.  There are about 200 species. All have Leaves with stipules (basal appendage of the petiole). Plants are often dioecious (having male and female parts on separate plants). Male inflorescences are larger. Small Flowers are in cymes, actinomorphic (regular, symmetrical), have a reduced calyx, lack a corolla and are wind pollinated. Number of stamens varies. Two connate carpels are present in the Pistil and here the Ovary is usually superior. Fruit in an Achene or a Drupe.

Name derivation: Celtis was used by Pliny the Elder (23AD–79AD) – Roman statesman and scholar. It is also the Greek name for Laurel tree. africana – from Africa. It is not related to Ocotea bullata the Black stinkwood, which is in the family Lauraceae. There are 3 indigenous species of the genus Celtis in Southern Africa. The other 2 are C. gomphophylla and C. mildbraedii.

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

Description. Spines are absent on this impressive Tree that is up to 12m high and 30m or more in a forest. The taller trees may form a dense curved or spreading canopy. In exposed rocky soil it may remain a shrub. It has a straight clean trunk, which may be buttressed (Photo 428). The Bark is pale grey to almost white and smooth without warts. Small horizontal lenticels (a usually raised corky oval or elongated area on the plant that allows the uncontrolled interchange of gases with the environment) on youngish branches and the trunk may be pitted in old trees.

Leaves

The initially a bright, translucent green Leaves are an attractive indicator of spring. The tree is deciduous – especially away from the coast. Where the winters are mild, the leaves may remain on the tree until the new, hairy leaves appear. The leaves are up to 13 x 7cm and alternatively arranged. They may be densely hairy and mature leaves become dark green, rough and less hairy. The Apex is long and may be caudate (having a tail-like appendage). The markedly asymmetric Base is entire (with a continuous margin, not in any way indented but may be hairy) and rounded or lobed to broadly tapering. There are 3 clearly visible Veins arising from the base. The Margin is wavy, hairy and at least half the upper edges are serrated with the teeth pointing towards the apex. In Trema orientalis the leaves are usually serrated almost from the base and have a more tapering tip. Towards the end of summer, leaves may become edged with yellow before falling. The hairy Petiole (leaf stalk) is short – up to 1cm long. Stipules (basal appendages of the petiole) fall early. The exotic Celtis sinensis, has leaves that are smooth and leathery.

Flowers

The individual inconspicuous, small, greenish and star-like Flowers are located on current season branches and occur with the new leaves. Flowers are monoecious (have separate sexes on different flowers that are on the same tree). Some flowers may be bisexual. Floral parts are obscurely spirally arranged. Flowers are without Petals. The sessile Male flowers are globular and in dense clusters at the base of new green leaves. Stamens arise from the pilose (covered with long, soft hairs) Receptacle (is that expanded tip of the flower stalk from which the floral parts develop) and Filaments are distinct and exserted after expanding. The 4-5 dorsifixed Anthers have 2 Theca (pollen sacs), which dehisce longitudinally. Female flowers are usually solitary, occurring in the leaf axils and are on branches of the current year. Among them may be a few bisexual flowers. Staminodes (sterile stamens) are usually present. There is a single Pistil (a unit of the Gynoecium, the female element of the flower, composed of the Ovary, Style and Stigma) and the single, superior ovoid Ovary is sessile and has a single Locule (cavity within an organ).  The Style is short – 2 to 5mm and divided into 2 divergent elongate lobes. (Aug-Oct).

Fruit

The small, fleshy ovoid, spherical or urn shaped Fruit is a Drupe (a fleshy, 1-seeded indehiscent fruit with the seed enclosed in a stony endocarp; stone fruit e.g. peach). It is about 12 x 8mm, and is yellow or brownish or red when mature. The drupes may be hairy or smooth and rest on thin stalks about 1,3cm long. They end with the twisted remains of the Stigma. The small Seeds contain a curved embryo and no endosperm (starch and oil containing tissue of the seeds). Seeds pass through the digestive system of birds. This enables them to be widely dispersed. (Oct-Apr).

Distribution & Ecology

Except for the arid central and west of the RSA, this tree grows almost everywhere from the coast up to 2 100m. Trees grow naturally in the Western Cape, Eastern Cape, KwaZulu-Natal, Free State, Mpumalanga, North West Limpopo, Swaziland, Mozambique, Zimbabwe, Botswana and as far north as Ethiopia but not in Namibia. Good examples can be seen in Pretoria at the parliamentary buildings and fountains. Larva of the African Snout Butterfly (Libythea labdaca laius) feed on the leaves. This is a migratory species. This tree is also the larval food plant for Blue-spotted Emperor butterfly (Charaxis cithaeron). Caloptilia celtina is a moth, the larvae of which eat the between the veins near the base of the leaves. Fruit is eaten by Cape and Blackeyed Bulbuls, Plumb coloured Starlings, Mousebirds, Karoo Thrush, Purple crested Louries (Purple-crested turaco), Crested and Black-collared Barbets. Baboons and monkeys also consume fruit. Large trees may be close to 100 years old.  The (photo 395) of the cross section is that of the lovely old Celtis in the tea garden in Walter Sisulu NBG that fell down in 2016. Judging from the rings, the tree appears to have be in the region of 90 years old.

Ethnobotany

The edible fruit is mealy and slightly sweet. This is a good bird tree and is a good nesting and resting site. Wood is dull white and possibly some green. It has been used, after seasoning in water (the wood is prone to borer attack), for making not very strong planks and furniture. Fresh Seeds should be collected from ripe fruit on the tree. These trees grow quickly (up to 2m per year) and are hardy. Keep clear of walls. Recently germinated seeds have a deep tap root and can become difficult to pull out. Moisten the soil and remove early if unwanted. Domestic animals (mainly cattle and goats) sometimes eat leaves. The tree is a good bonsai plant.

References

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

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

Ginn, P.J. McIlleron, W.G. Milstein, S. 1989. The Complete Book of Southern African Birds. Struik Publishers (PTY) LTD. Third impression 1991.

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.

http://redlist.sanbi.org/species.php?species=3436-1

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

http://archivedpublicwebsite.up.ac.za/default.asp?ipkCategoryID=20815&subid=20815

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

http://witkoppenwildflower.co.za/celtis-africana/

http://www.biodiversityexplorer.org/plants/cannabaceae/celtis_africana.htm

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

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

Alice Notten: help with the family name.