Appearing somewhat like palms or ferns, African cycads are primitive trees, native to the southern half of Africa. As part of the family Zamiaceae, African cycads display many similarities to their relatives in other genera.
Like other cycads, African varieties produce a circular ring of compound leaves at the top of their trunks. Most species have distinct trunks, although other species grow as multi-trunked “shrubs.” Some species, such as Encephalartos hirsutus, produce ground-hugging stems. Suckers commonly emerge from the base of the trunk in many species.
Like other cycads, these are dioecious trees, which produce either male or female cones. Many people find the odor associated with the male cones to be rather off-putting. The seeds of these gymnosperms are often brightly colored, which probably helps them to attract predators, who may spread the seeds in their droppings.
Like the other cycads, African cycads are usually rather small. However, Encephalartos laurentianus – the largest species in the genus – occasionally exceeds 45 feet in height. Another species, Encephalartos transvenosus reaches similar heights, and may reach 40 feet in height.
The genus Encephalartos contains approximately 60 to 65 species; the exact figure varies depending on the authority consulted. The majority of the species are sun-loving plants that require well-drained substrates. Some consider these cycads to be succulents, as they store water in their trunks.
Some African cycads are very poorly understood by botanists, and they appear to be quite rare in the wild. Many are listed as “Endangered” or “Critically Endangered” by the IUCN Redlist of Threatened Species. For example, only a single male specimen of E. woodii is known to exist in the wild. The specimen, which was first documented in 1895, grows in the Ngoye Forest, in Zululand. Several other specimens – all derived from cuttings taken from the original wild plant – grow in a handful or arboreta and botanical gardens.
Others have only been found in a very restricted range. For example, the vast majority of E. aemulans live on a single hill in the Natal region of South Africa. It is possible that the species’ former range was more extensive, as two aged male specimens are located about 5 miles away from the hill. This species was only formally described in 1993, and prior to this, many specimens found their way into the ornamental plant market. Currently, the wild population is protected, and, according to the Gymnosperm Database, the location has not been made publicly available.
By contrast, other species of the genus are thought to have relatively healthy, stable populations. Some species are imperiled in one part of their range, yet safe in other locations. For example, most Kenyan giant cycads (E. tegulaneus) populations are stable, but some are critically endangered.
Like many close relatives – including sago cycads (Cycas revoluta), among others – African cycads harbor edible starches in their trunks. This material usually undergoes quite a bit of processing before it is consumed, as the material contains poisons. Nevertheless, several members of the genus are colloquially called “bread trees” in their native range. The hollow trunks of some African cycads are used as water dishes for livestock.
Several African cycads are popular ornamental plants. E. altensteinii and E. ferox are two of the most widely available species, but E. arenarius, E. cerinus and E. kisambo are relatively common as well.
Various primates, rodents, birds and other wildlife species consume the fruits, as do some humans from the region. The outer portions of the kernel are regarded as edible, while the internal kernel is quite toxic; however, many authorities recommend against eating the seeds entirely.