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Encephalartos dyerianus - Specie described by Lavranos & Goode  (Lillie Cycad)


Description
The stems are well-developed and robust, unbranched but often suckering from the base. Stems can be up to 3m or occasionally 6m tall and 300mm to 400mm in diameter.

Plants have numerous leaves, arranged in a dense crown. Leaves are conspicuously glaucous ("blue"), straight and rigid. Length varies from 1.4m to 1.7m with a petiole no more than 60mm long.

The pinnae are directed towards the apex of the leaf at an angle of about 45° with the rachis, with opposing leaflets set at an angle of about 140° to each other. The leaflets are not, or only slightly overlapping, and the lower leaflets are gradually reduced to prickles towards the base of the leaf. The median leaflets are 170mm to 240mm long and 13mm to 18mm wide, very narrowly elliptic and somewhat curved. The apices are spinescent and somewhat turned in the direction of the leaf apex. There are several teeth on both margins of seedling leaflets but without any teeth on leaflets of mature plants.

The male and female cones are quite different, but both are hairless with the scale faces smooth and bluish green. Five to eight male cones per stem has been observed. These are narrowly egg-sbaped, 270mm to 460mm long and 90mm to 120mm wide. Cones are borne on a 100mm to 170mm long peduncle. The central facet of the cone scale face is slightly raised, but not drawn out into a beak or lip. The female cones number 4 to 5 per stem. They are cylindrical, 300mm to 600mm long and 100mm to 200mm wide. They appear to be sessile, but are carried on peduncles up to 120mm long which are hidden amongst the scale leaves in the crown of the stem. Each cone contains about 200 seeds and the sarcotesta is orange-brown in colour.


Distribution & Habitat
E. dyerianus occurs mainly on a low granite hill, at an elevation of about 700m above sea level, a few kilometers north of Mica in the north-eastern Transvaal. This area consists of plains covered with mopane trees (Colophospermum mopane), and interrupted by a series of rather similar granite hills. Inexplicably E. dyerianus grows on only one of these hills. Near Gravelotte a few scattered plants have been located in the mopane bush, but these are too few and too scattered to reproduce from seed. On average this area gets an annual summer rainfall of 400mm to 500mm, and summer temperatures get very high amongst the granite boulders where E. dyerianus grows wedged into crevices, in blazing sunshine.

Cultivation & Propagation
E. dyerianus is an easy species to grow from seed. It is fast-growing and without problems once planted out in the open ground, provided that it is in a very well-drained and sunny location.


Notes
Encephalartos dyerianus, its name honouring Dr. R.A. Dyer who did so much to further our knowledge of the South African species of Encephalartos, shows two trends typical of recently described Encephalartos species. Firstly it was possible to distinguish it as a separate species as a result of better understanding of taxonomically important characteristics. The second is that the species has an extremely restricted geographical distribution. However, in contrast to some other recently described species, there are a considerable number of individuals.

This species was first discovered in the early 1970's. At that stage the variation in the glaucous- ("blue-") leaved Transvaal species was still imperfectly understood. In addition there was a feeling that new species of Encephalartos should not be described as it invariably led to an uninhibited rush by collectors to procure specimens, without regard for the survival if the species in nature. In 1988 Robbertse et al. published it as a new species under the name E. graniticolus, but the paper was pre-empted by an article by Lavranos & Goode in which they published it under the name E. dyerianus. In terms of the International Code of Botanical Nomenclature the name E. dyerianus has priority.

For a change the conservation status of this species is a happy story. The hill on which these plants were first discovered, contains about 600 plants which produce large amounts of viable seeds during good years. In fact, the plants grow so densely that the sight is only surpassed by that of E. transvenosus at Modjadji. Some years ago hundreds of seedling were raised by the then Transvaal Division of Nature Conservation and sold to the public under the name E. eugene-maraisii, so that it is quite well established in older collections. One reason for the successful conservation of this species is that practically the whole population is concentrated on a single hill, which made it practical to fence the site and appoint a permanent guard who is on duty 24 hours a day. It is now a nature reserve administered by the Transvaal Chief Directorate of Nature Conservation, as the Lillie Flora Reserve.


References & Acknowledgements

  • Encephalartos Vol 29: Focus on Encephalartos dyerianus - Piet Vorster
  • SPECIAL THANKS TO THE CYCAD SOCIETY OF SOUTH AFRICA www.cycadsociety.org