Encephalartos heenanii – Dyer (1972)
xxx Cycad (Eng), xxx Broodboom (Afr)
Category: Threatened & Protected
The stems of Encephalartos heenanii are well-developed and suckering or branching from the base. Mature trunks are erect or become procumbent with age. They are up to 3m long and 400mm in diameter. The cataphylls are linear-lanceolate, often persisting in a dry brittle form on the upper half of the trunk and are very densely woolly with long golden brown hairs in the crown.
Leaves are 1m to 2m long, the rachis is incurved and often slightly twisted at the apex, giving a “cup-like” appearance to the plant’s crown. The petiole can be up to 200mm long and is round in cross section.
Median pinnae are succubously orientated, ascending in the plane of the rachis and markedly reflexed from the rachis. Leaflets are oblong-lanceolate in outline, 100mm to 150mm long and up to 20mm broad. The margins are entire or have 1 to 2 teeth. The lower leaflet surface has prominently raised veins and while the upper surface often has small wart-like protuberances. Lower leaflets are reduced but not to a series of prickles.
Male cones are usually single or in groups of 2 to 4. They are sub-cylindrical in shape and pedunculate. They are 270mm to 300mm in length, 120mm to 180mm in diameter and covered with dense brown wool. Cones are seldom glabrous. The male cone is similar in appearance to the female cone. A single female cone is usually produced and rarely 3. It is pedunculate, broadly ovate and 200mm to 350mm long, 170mm to 200mm in diameter and covered with dense shaggy golden hair but is often a glabrous yellow.
Distribution & Habitat
This species is known with certainty from a very small mountainous area on the border between Swaziland and the Republic of South Africa. It grows in open grassland on steep slopes at an altitude of about 1500m. The climate is hot in summer and cold in winter. The area gets summer rainfall of 1200mm per annum.
Cultivation & Propagation
This species has little horticultural potential and is notoriously difficult to cultivate. Mature plants seldom survive transplanting and desiccate easily after removal. Plants are also prone to fungal attack after transplanting. Seedlings are rare in trade, due to the fact that plants seldom cone in cultivation. Plants are rarely seen in cultivation and will probably always be a sought after collectors item.
The Makonywa, Ngwenya and Big Buffalo ranges form part of the most eastern outliers of the south eastern Transvaal Drakensberg. They are home to many endemic animal and plant species, including three of southern Africa’s rarest cycads, E. paucidentatus, E. laevifolius and E. heenanii. The first indications of the latter species’ existence came from the exploration work of Mr. Denis Heenan in the Piggs Peak district of Swaziland in 1969. The new taxon was found growing in close proximity to large populations of E. paucidentatus and E. laevifolius, and the first thought, which could not be ignored, was that it could be a hybrid between these two unlike species. No supporting evidence for this idea was found, however, and the lack of fresh cones hampered the description of the species. It was not until 1971 that patient fieldwork by Mr. Heenan and his son David, were rewarded with the discovery of fresh cone material, which were sent to the late Dr. A Dyer at the then Botanical Research Institute. The description of E. heenanii was published in 1972 and honours the role played by Mr. Heenan in its discovery.
This species has clear affinities with the E. transvenosus / E. paucidentatus group. It shares similar characteristics, although the plants are much smaller in stature. E. heenanii is probably most closely allied to E. paucidentatus and several natural hybrids between the two species have been noticed. The two species share such characteristics as the reflexed leaflets (in some E. paucidentatus specimens at least) and the prominently raised veins on the lower leaf surface. The relationship of E. heenanii with plants from the Lebombo Mountains east of Stegi in Swaziland needs some investigation. These plants have inflexed leaflets, densely golden woolly cataphylls and the veins are also prominently raised on the leaflet abaxial surface, but the leaves are straight in comparison with the characteristic incurved leaves of E. heenanii.
It appears as if this species was never abundant and illegal collecting, even in the years before formal description, has reduced numbers in the wild to near extinction. Plants are presently conserved in the Somgimvelo Nature Reserve (RSA) and the Malolotja Nature Reserve in Swaziland. During a survey in 1985, it was found that fewer than 500 plants existed in the wild. Few cycads have captured the imagination of collectors as E. heenanii has. It appears as if the inaccessibility of the terrain is no deterrent to poachers who even hire helicopters to remove mature specimens. It is a sad state of affairs that there are more mature specimens of this species in cultivation than in nature. This species must be considered as endangered and close to extinction by conservation authorities. This is mainly due to the taxon’s severely restricted distribution, intensive pressure from collectors, its inability to reproduce sexually, inter specific hybridization, encroachment on it’s habitat by forestry activities, cultural and medicinal use and the presence of possibly introduced fungal pathogens. An intensive exsitu conservation project has been started in the Lowveld National Botanical Garden and it is hoped that this species will be saved from extinction.