Encephalartos ngoyanus — the Ngoye dwarf cycad

Introduction

Encephalartos ngoyanus is a small cycad with a subterranean stem that is kept underground by contractile roots. This cycad rarely produces suckers, unless growing in rocky crevices where the stems are forced above the rock, which induces suckering.

Description

The stem is subterranean, usually single, up to 300 mm long and 200 mm in diameter, however, plants with as many as 5 stems have been recorded. The strong contractile roots (roots that contract, pulling the plant back into the ground) keep the stem underground, unless the plant is growing in rocky crevices, where the stem is forced above the rock and this will also induce rare suckering.

Leaves are medium sized, about 0.6–1.25 m long, 5 to 10 leaves per plant, straight, dark green on the upper side and lighter green on the underside, young leaves are covered with fine white woolly outer layer which remains on mature leaves on the rachis and underside of the leaflets. Leaflets linear, 70–120 mm long and 9–13 wide, soft, evenly spaced throughout, with margin entire. Basal leaflets are reduced to 1 or 2 spines. Petiole is 100–150 mm long, swollen leaf base covered with white or brown hairs.

Both genders produce one cone per plant, initially light green but becoming yellow when mature. Male cone is egg-shaped, 200–250 mm long, 100–120 mm in diameter, and is produced in midsummer (December to January), with pollen shedding taking place in late summer to early autumn (February to April); peduncle 50–65 mm long. Female cone is pear-shaped, 200–250 mm long, 100–120 mm in diameter, with peduncle 50 mm long but completely covered by the woolly hair of the stem apex; cone disintegrates in summer (August to October). Seeds are bright red and 29 mm long, 18–20 mm in diameter.

Conservation status

According to the Red List of South African plants website, this cycad is assessed as Vulnerable ( VU ). According to records, the remaining population size is estimated to consist of fewer than 5 000 mature individuals in the wild and several subpopulations are declining. The main threat is harvesting of wild plants for private collections, overgrazing of its habitat, frequent veld fires and E. ngoyanus is a slow grower that does not reproduce frequently in nature. Past decline is suspected to be over 20% and future decline is likely to exceed 10% over the next generation (30 years).

Distribution and habitat

Encephalartos ngoyanus occurs naturally in northern KwaZulu-Natal from the Ngoye Forest, to the area surrounding the towns of Mkhuze and Ubombo, and at the Jozini Dam and on both sides of the border between KwaZulu-Natal and Eswatini (Swaziland). It grows on rocky slopes in open grasslands and along the forest margins. The habitat receives a rainfall of 750–1 000 mm per annum.

Derivation of name and history

The genus Encephalartos was described by the German botanist Johann Georg Christian Lehmann in 1834. The epithet is derived from Greek and means ‘bread in head’ and refers to the floury, starchy material in the trunks of some species, which is used as famine food by local people. This species was described in 1949 by Inez Clare Verdoorn. The specific epithet ngonyanus refers to the Ngoye Forest area of KwaZulu-Natal, where this cycad was obtained. Ngoye Forest is coastal scarp forest located between Mthunzini and Empangeni in KwaZulu-Natal. This forest is also the original habitat of the now extinct in the wild Encephalartos woodii . Another cycad growing in this forest is Stangeria eriopus .

Cycads are grouped into 3 families: Cycadaceae, Stangeriaceae and Zamiaceae. Currently there are about 343 cycads recognized worldwide. Cycads are found in the tropical, subtropical and warm temperate regions of Africa, Asia, Australia, and North, and Central America. South Africa has the most cycad species in Africa, with 38 species, all in the genus Encephalartos of the family Zamiaceae, and one Stangeria. South Africa also has the most threatened species: 3 species are Extinct in the Wild (EW) and 12 species have been listed as Critically Endangered (CR), and likely to soon be extinct in the wild.

This species is closely related to and often confused with Encephalartos caffer (Eastern Cape dwarf cycad). They can be distinguished as follows:

E: ngoyanus : the proximal half of the leaf often curves upwards, whereas the distal half is more or less straight. The upper side of the leaflets is soft and glossy. The lower leaflets surface feels less smooth than the upper one when stroked gently with the fingers.

E. caffer : the leaves are either straight or curve gradually downwards. Leaflets are leathery with a dull green colour and are usually disorderly arranged on the rachis. The leaflets are very crowded, especially in the distal part of the leaf. Both sides of the leaflets feel equally smooth.

Ecology

Encephalartos ngoyanus occurs in grassland and grass fires are common in this type of habitat and fire plays a very important role in stimulating coning in the plant, but too frequent fires have become a threat to the cycad.

For a long time it was thought that all cycads were wind pollinated, as most coniferous plants are, and the fact that cycads generally produce high volumes of pollen, supported this argument. However, objections were raised based on the following points: species such as  E. cycadifolius ,  E. ghellinckii ,  E. heenanii ,  E. friderici-guilielmi  and  E. lanatus  have very woolly cones, which make it difficult for wind pollination to happen. Other cycad species such as  E. villosus  and  Stangeria eriopus  occur in forest where there is no wind. Current research shows that insects are the pollinators of all 10 cycad genera. Most cycads are thermogenic (able to produce heat) and emit volatile odours. In nature when the male cone reaches maturity, the central axis elongates and the scales move apart to make room for the release of the pollen, which is distributed by insects. The release of pollen varies between species but usually lasts for 2 weeks, on average. At the same time, the female cone also reaches maturity, the cone heats up, causing it to elongate, and it produces a smell, which attracts the insects, the pollen vectors, to the female cone. The scales move apart to allow the insects to enter and to pollinate the cone.

Uses

In the isiZulu language, most of the cycads are referred to as isqgiki – somkhovu. This name refers to witchcraft practices, where a person is converted into becoming a zombie and is used for witchcraft. The cycad is planted in front of the gate of the homestead to protect it from the evil spirit. If someone practices any witchcraft using umkhovu , this zombie will sit on top of the cycad, which is referred as isqgiki , which means ‘chair’, and that is where the common name is derived from.

This species is hardly used in cultivation. But it can be a great addition to most gardens and landscapes, easy to fit in even tight garden spaces, especially as an understory plant, but be sure to purchase your plant from a legal supplier.

Growing this species

Encephalartos ngoyanus grows best in dappled light. Although this is a slow growing cycad, it does well in cultivation provided that it is planted in well-drained soil. This species will tolerate light frost, is sensitive to overwatering, as a result in cold areas plants often shed leaves in the autumn and should then be kept in dry condition.

Encephalartos ngoyanus is mainly propagated by seed since it rarely produces any suckers. Sow seed in riversand and place on a heated bench at 24–28ºC. Germination should start 3 weeks after sowing. However, some seeds will take longer, especially where there is no heat. At the one-leaf stage of development, the seedlings are susceptible to infection by the fungus that causes damping off.