Encephalartos lebomboensis – Verdoorn (1949)

Lebombo cycad (Eng), Lebombo broodboom (Afr)

Category: Endangered

 

Description


The stems of Encephalartos lebomboensis are similar to those of E. altensteinii and E. natalensis but rarely exceed 4m in height or 25cm to 30cm in diameter. They usually show a pattern of alternating bands of large and small leaf bases reflecting either the wet and dry periods in the plant’s history or perhaps its coning cycles. The crown may be quite woolly, especially at coning times. Stems are generally unbranched, but suckers arising at the base may develop into mature trunks.

Leaves vary from a fresh bright green to a glossy darker green and are borne in a dense crown. They vary from 1m to 2m in length and are fairly straight but may be slight recurved towards the apex. Emergent new leaves are hairy but these hairs are soon lost as leaves mature.

The leaflets vary from being set horizontally into two longitudinal grooves along opposite sides of the rachis without much overlapping, to being set at a slight angle so as to overlap downwards. Median leaflets are typically 12cm to 18cm long by 1,2cm to 2,2cm wide. Although sometimes without teeth, the leaflets usually have 1 to 4 teeth on both margins, often more teeth on the lower than the upper margin. Leaflets become progressively reduced in size towards the leaf base, ending in a series of small prickles.

E. lebomboensis bear 1 to 3 male cones, which are about 45cm long and 12cm to 15cm in diameter, narrowing gradually towards each end. Cones are usually apricot-yellow in colour and are supported on a short peduncle. Median cone scales are 3.5cm long, 4cm broad and 1.5cm thick with the outer face projecting into a short beak. Female plants also bear 1 to 3 egg-shaped cones, which are 40cm to 45cm long by 22cm to 30cm in diameter. These vary somewhat in colour from a rich apricot-yellow, through to a pale cream colour. Median scales measure about 6cm long by 4,5cm broad by 3,5cm thick. The face of the female cone scales is typically smooth and flat, protruding only a short distance outwards. Seeds are some 4cm long by 1.8cm to 2.2cm in diameter with a scarlet sarcotesta. The sclerotesta measures typically 2.6cm long, 1.8cm in diameter and displaces a volume of 4.5ml. It is buff coloured with 10 to 13 prominent longitudinal ribs and has tiny wart-like protruberances near the micropyle.

Female cones

Male cones

Leaf detail

 

Distribution & Habitat


E. lebomboensis occurs in comparative abundance in rocky slopes of the Lebombo Mountains, principally in the catchment areas of the Pongola, Ngwavuma and Usutu Rivers. This area includes a large part of eastern Swaziland, and smaller areas in southwestern Mozambique, northern Natal and the southeastern Transvaal. The main towns in this area are Siteki and Big Bend (Swaziland), Ingwavuma, Jozini, Ubombo and Paulpietersburg (Natal) and Pongola and Piet Retief (Transvaal). The area enjoys a summer rainfall of 625mm to 750mm p.a.
Cultivation & Propagation


E. lebomboensis appears to produce highly viable seed, which is easily germinated (see BOTHALIA 8. p 418). The plants grow relatively quickly in suitable garden conditions, reaching appreciable size within 5-10 years. They are best sited in a well-drained area in full sun but also make good container specimens. The species is only semi-hardy to frosts.

 

Notes


Although it is difficult to credit anyone person with the “discovery” of the plant we know now as E. lebomboensis, it was one Captain D.R. Keith who first drew the attention of botanists to its existence. Keith, in the late 1920’s, found a large colony of cycads on rocky ridges of the Lebombo Mountains about 12 km south-east of Stegi (now Siteki) in Swaziland. He transplanted a number of these plants to create an avenue of cycads leading to his home “Ravelston” nearby. In 1935 he sent specimens to Kirstenbosch and Ewanrigg gardens. In 1945 M.R. Henderson, working at the Compton Herbarium, examined a number of cycads collected by 0. West near Ingwavuma in northern Natal. He concluded that there could be little doubt that “West’s Cycad” was an undescribed species. The magistrate at Ingwavuma, Mr. L.H. Conyngham, made a fairly extensive survey of the cycads between Ingwavuma and Siteki and then acted as guide for a botanical party – which included Inez Verdoorn – to tour the area. From the notes prepared on that trip, Dr Verdoorn confirmed that these plants were in fact distinct from E. altensteinii. Naming the species E. lebomboensis, she chose the type specimen from the large concentration of plants near Siteki and the official publication appeared in the Flowering Plants of Africa, Volume 27, of 1949. Dr Verdoorn was careful to note that the Ingwavuma plants “had stems more woolly at the crown and the cones with scale faces somewhat more prominent and pubescent” than those at Siteki. In separating the new taxon from E. altensteinii, emphasis was threefold: firstly the Lebombo plants were smaller in overall size, secondly the leaflets were reduced to prickles towards the leaf base, and thirdly cone scales were less pronounced.