WHO GETS THE ACACIA?

To different continents the acacia is more than just a tree. To us the acacia is part of our African landscape and the acacia name is as much a part of Africa as the Big Five. Since the Swedish botanist Carl Linneus first described the type species of the genus Acacia in Africa in 1773, continents could lay claim to acacia trees. In the last 30 years, this has all changed. The anatomic and genetic analysis now available to taxonomists clearly demonstrates to them that the Australian and African acacias do not belong in the same genus at all.

 

Who then, Australia or Africa should be allowed to use the name Acacia?

The first type species, Acacia nilotica (scented thorn) was found in Africa and so named based on this tree’s best known range along the Nile River, but Australia has the majority of species. Australia has approximately 960 species of acacia tree’s that are Indigenous to their continent compared with Africa’s approximate 130.

Every 6 years, when the International Botanical Congress meets, it tackles a backlog of problems related to the naming of plants. At the Botanical Congress in Vienna in 2005 the issue appeared to have been resolved, when the delegates decided that the Acacia would belong to Australia.

Another 6 years of debate followed, culminating in an appeal against the decision.

Then in 2011, at the Botanical Congress held in Melbourne, Australia the 2005 decision was upheld.

Australia’s acacias will continue to be known as acacias and the new type species will be the Australian Acacia penninervis. The African species, previously called Acacia, will be assigned to the genus, Vachellia and Senegalia. The decision that Australia was entitled to the name Acacia appears to have gone against the normal rules of taxonomy (the science that gives names to all living organisms both alive and extinct). In taxonomy the accepted rule is that the earliest published name has precedence. The rule was waived by the Congress, claiming special circumstances; despite the first Acacia named was an African tree.

 

What happens now in Africa?

A simple rule is the larger trees like the umbrella tree, Acacia tortillis will be known as Vichellia tortillis while, and multi-stemmed mellifera type versions look set to become Senegalia. Good news though is there is no need to change the common names. Tree books still refer to ‘our Acacias’ as Acacias. We will in time get used to the name change to Vichellia and Senegalia just as we have adjusted and grown accustomed to the bird name changes. On the Greater Woodmead Estate we have 8 acacia tree species: SA162 Acacia caffra = Senegalia caffra (common hook-thorn, cat thorn); SA166 Acacia galpinii = Senegalia galpinii (monkey thorn) SA 168 Acacia erioloba = Vachellia erioloba (camel thorn) SA 172 Acacia karroo = Vachellia karroo (sweet thorn) SA 182 Acacia rehmanniana (silky thorn) SA 183 Acacia robusta = Vachellia robusta (ankle-thorn) SA 187 Acacia sieberiana = Vachellia sieberiana (paperbark acacia) SA 189 Acacia xanthophloea = Vachellia xanthophloea (fevertree)

COMMON HOOK THORN, CAT THORN

SA 162 Acacia caffra = Senegalia caffra

Over the next couple months I will write on our 8 acacia tree species that can be seen on the Greater Woodmead Estate and include further information on acacia trees per se. Together with the wild pear tree (Dombeya rotundifolia), and the coral tree (Erythrina lysistemon ) the common hook-thorn tree is one of the earliest to flower in spring ,producing strongly scented creamy-white flower spikes that turn yellow with age. Here in October, when the veld is still quite brown after months of no rain, beautiful splashes of pale yellow flowers become noticeable dotted across the bushveld. The main flowering occurs in October and can sometimes last through to November. These flower spikes are quite large and conspicuous and look rather beautiful against the backdrop of new leaves. The flowers are followed by narrow, straight, flat pale brown – red pods which ripen in mid-summer. The two pristine bushveld areas, referred to as Wilds East and Wilds West that are to the right and the left hand sides of the road after entering through the boom gate onto the Greater Woodmead Estate, is dotted with this beautiful tree. The common hook-thorns do particularly well in this slightly warmer area of the Estate and as a general rule they occur naturally in a wide variety of habitats from coastal scrub to bushveld and Highveld grasslands.

Other fine examples can be seen along the left side of the Golf Data brick pathway that runs along the length of the driving range.

The common hook-thorn, and probably better referred to as a cat thorn tree, because when a branchlet catches you, you know about it. It is a small deciduous tree, and often with a crooked single or multi-stemmed trunk which in fact gives this tree wonderful character.

Its thorns are not large white thorns but rather small, hooked thorns. The leaves are similar to most acacia varieties. The first leaflet is divided into many smaller leaves. The new leaves are soft fresh green and feathery looking. The leaves are drooping, which gives the canopy a lovely soft look.

Several butterfly species breed in galls (swellings) on the branches of the tree.

Leaf infusions, whereby leaves are soaked in cold or boiling water for a while can be used to cure the occasional stomach ache in children. The wood makes excellent fence poles, is used for tanning, and the beautiful root wood is highly valued by Xhosa women for tobacco pipes. The Acacia caffra is regarded as a lucky tree in traditional African beliefs.

Fayne Connelly

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