Rounding off the top five (or is it six?) largest tree families in southern Africa is the Anacardiaceae or mango family. The Anacardiaceae contains about 80 native tree species, and most have either simple or compound, imparipinnate (i.e. pinnate with a single leaflet at the apex) leaves, and a watery or milky latex, which can cause irritation to the skin. The crushed leaves usually smell like turpentine or resin.

The largest and most familiar genus is Searsia (previously known as Rhus). Searsia species are trifoliolate (meaning that there are three leaflets) with small spherical or ovoid fleshy fruits (called drupes). The genus is named for Paul B. Sears (1891–1990), an American ecologist, who was head of the Yale School of Botany. Sears worked on the flora of North America, notably Ohio, where several Rhus species are found. In southern Africa there are approximately 47 described species, with many of these being very difficult to tell apart. Searsia burchellii (shown below) is named after William John Burchell (1782–1863), an English naturalist who traveled in southern Africa and collected thousands of plant specimens, including this species.

Another notable native genus in the Anacardiaceae occurring in southern Africa is Ozoroa, the resin trees. This genus of shrubs or small trees currently contains 14 species, some of which are very rare (e.g. O. namaquensis). Several other native genera are mono-specific, including Protorhus (the red beech), and Heeria (rockwood).

Culinary delights!

Many trees of the Anacardiaceae are often delicious! The most delectable native fruit is certainly that produced by the marula tree, Sclerocarya birrea. Although the marula is most commonly associated with an alcoholic drink (the fruits are often fermented and incorporated into a rich, creamy synonymous drink), the raw fruits are richly scented and taste delicious! I recall being initially skeptical when offered some of these fruits by my MSc supervisor (Prof. Jeremy Midgley from the University of Cape Town). But once I tasted the fruits, I could not get enough of them! A bonus is that they contain about four times as much vitamin C as an orange!

Many of the other culinary delights are produced by trees introduced into southern Africa from elsewhere. There are some really great nuts: pistachio nuts from the pistachio tree (Pistacea vera) and cashew nuts from the cashew tree (Anacardium occidentale). The latter nuts contain approximately 45% fat and 20% protein, which explains why they are so tasty. Pistachios were introduced from the middle east and the cashew was originally from tropical America. The most famous fleshy drupe is of course the mango from the mango tree (Mangifera indica). Mango trees were introduced from tropical east Asia and are now grown extensively in sub-tropical areas.

So the Anacardiaceae is the most delicious family. But beware! Not all species are palatable; some are highly toxic. The “pain bush” (Smodingium argutum) and “agony tree” (Trichoscypha ulugurensis) can both cause severe allergic rashes if touched (similar to the dreadful species that I encountered many times during field work in California: Toxicodendron diversilobum, otherwise known as poison oak). Smodingium has also been refered to as “the terrible tovana plant of Pondoland” (tovana is of Xhosa or Zulu derivation).