Encephalartos lehmannii – Ecklon and Zeyher (1834)
Bushman’s River cycad, Karoo cycad (Eng), Karoobroodboom (Afr)
Encephalartos lehmannii is not a very tall growing cycad. The stems are usually short and sturdy, up to about 1,5m in length. Stems of 2m and taller are very rare. The diameter of the stem usually ranges between 25cm and 50cm. Although plants with single stems occur, it is more usual to see plants with two or more stems, branching from the same base. Some of these stems may be procumbent or curved. Occasionally “two-headed” or “multi-headed” stems are found. This is usually the result of damage to the growth point of the original stem. Stems with side stems are also sometimes seen, but these are rare. These branches probably originate where a stem is damaged. Like in other cycads, the stem is covered and protected by a layer of persistent old leaf bases.
The leaves of E. lehmannii are 1m to 1,5m long, including the leaf stalk which is up to 25cm long. The rachis is stiff and nearly straight, except for the tip, which may curve back slightly or may occasionally be somewhat twisted sideways. The leaf base is quite large and has a conspicuous red-brown to yellow-brown collar. The leaves have a grey-blue colour when young, but may become green with age.
The pinnae at the middle of the leaf are approximately 12cm to 18cm long and 1,5cm to 2cm broad. The leaflets closer to the tip and the base of the leaf are smaller. Towards the base they are reduced in size to possibly one prickle. The leaflets are usually without teeth, although an occasional tooth or two may occur on the margin. The leaflets are attached to the rachis in such a way that they are horizontal to the rachis, but that they form a V along the leaf. They are well spaced, especially towards the base of the leaf. Towards the tip they are closer together but seldom overlap much. The leaves of seedlings are quite short with relatively few leaflets (8 or 10). The seedling leaflets have a number of teeth at its tip. The seedling leaflets are also well spaced.
Single cones are borne by both female and male plants. In both sexes the colour of the cone is blackish-red as a result of short black hair which covers the ends of the cone scales. These are actually green in colour under the layer of hairs. The cone is borne on a short, stout stalk. The male cone is more or less cylindrical in shape, but narrower towards the base and the tip. It is 25cm to 35cm long, with a diameter of 8cm to 10cm. The cone is made up of spiral rows of cone scales, each about 2,5cm broad and lcm thick. The end of each scale forms a beak which projects about 1,5cm. The bottom surface of each scale is covered with pollen sacs. The female cone is more or less barrel-shaped and 30cm to 50cm long, with a diameter of 15cm to 25cm. The cone scales at the middle of the cone are about 6cm long, 6cm broad and 3,5cm thick. The scale has a beak which projects approximately 2cm. The face of the cone scale is almost smooth. Mature cones lose the layer of fine hair and have more of a green colour. Two seeds are formed on top of each cone scale. The fresh seed has a bright red cover and is approximately 5cm long and 2cm in diameter.
Distribution & Habitat
E. lehmannii is the cycad species most closely associated with the dry regions, particularly the Karoo. It may also be the species which occurs furthest to the west. It occurs on cliffs and mountain sides in the Eastern Cape Province in the districts of Willowmore, Steytlerville, Uitenhage, Pearston and Bedford. It grows on the Klein Winterhoek Mountains and Groot Bruintjieshoogte in the drainage areas of the Groot and Sundays Rivers. Plants usually grow on sandstone hills and mountainsides amongst Karoo scrub vegetation. It is often associated with the Euphorbia species (“noorsdoring”) which is so characteristic of this part of the Karoo. The climate in its distribution area is dry, with very hot summers. Night temperatures drop to extremes in winter and frost occurs. Rain falls mainly in summer and the annual rainfall is seldom higher than 350mm. Prolonged droughts occur periodically.
In the Uitenhage district the distribution areas of E. lehmannii and E. horridus are close to each other. No hybrids have been described officially, but there are reports of hybrids between the species. If hybrids do occur, they are rare. North of Uitenhage, E. lehmannii also grows in close proximity to E. longifolius, but no hybrids have been reported.
Cultivation & Propagation
E. lehmannii grows quite well in the garden and it’s blue-grey leaves can be very attractive and effective in a well-planned garden, for example as a contrast plant. It also blends in well in a rock garden, amongst aloes and other succulent plants. The soil should be very well drained, fertile and neutral to alkaline and it should be grown in full sun. If it is grown in the shade, the leaves will loose their blue-grey colour and become green. Plants should not be over watered. E. lehmannii is able to resist long periods of drought and plants should not be over watered. It is also hardy to frost.
Seeds of E. lehmannii germinate easily and this species can quite easily be grown from seed. Seedlings do not grow very fast and the leaves remain relatively short for a number of years.
E. lehmannii did not enjoy such a well-documented discovery as E. longifolius and E. caffer. It was identified and named in Europe from material collected in South Africa, probably by plant collectors in the eighteenth century. The earliest names which seemed to have applied to what later became E. lehmannii, are Zamia pungens (given by Aiton in 1813) and Zamia lehmanniana, given by Ecklon and Zeyher in 1833 and named after Prof. J.G.C. Lehmann of Hamburg, Germany.
When he created the genus name Encephalartos in 1834, Lehmann transferred both these names, as E.pungens and E.lehmannii respectively. In 1933 J. Hutchinson and G. Rattray reduced E. pungens to E. lehmannii. At the same time they also reduced to E. lehmannii a number of the previously named species and varieties, including Zamia spinulosa, Zamia elongata, Zamia occidentalis, Encephalartos spinulosus, E. elongatus, E. mauritianus, E. lehmannii var. spinulosus, E. lehmannii var. dentatus and E. horridus var. trispinosa.
It became evident that there were wide variations amongst the plants grouped together as E. lehmannii by Hutchinson and Rattray and in 1965 Dr R.A. Dyer divided E.lehmannii into three different species: E.lehmannii, E.princeps and E. trispinosus.
Until fairly recently, E. lehmannii occurred in relatively large numbers. This situation seems to be changing rapidly and numerous plants have been removed from their habitat by collectors, especially those closer to main roads. Most of those which remain are high up in the cliffs in relatively inaccessible terrain. E. lehmannii is in need of strict protection, especially since it is nowhere specifically protected in any reserve by the province or the state and occurs only on privately owned land. The establishment of one or more nature reserves which would include viable colonies of E. lemannii could save this beautiful species from extinction.