Sclavo's cycad

Description

Encephalartos sclavoi, common name Sclavo's cycad, is a critically endangered cycad in the family Zamiaceae. It is endemic to Tanzania, with a population of only ~50 mature plants. Encephalartos sclavoi grows to about 1 metre (3.3 ft) high. The leaves are 170 to 200 centimetres (5.6 to 6.6 ft) long, dark green and semiglossy. Its seed cones are yellow, being 30 to 40 centimetres (12 to 16 in) long and 15 to 20 centimetres (5.9 to 7.9 in) in diameter. It was described in 1990 by Aldo Moretti, D.W. Stevenson and Paolo Deluca, honoring Jean Pierre Sclavo, a French collector of cycads, who first discovered this species. Encephalartos is a genus of cycad native to Africa. Several species of Encephalartos are commonly referred to as bread trees, bread palms or kaffir bread,since a bread-like starchy food can be prepared from the centre of the stem. The genus name is derived from the Greek words en (within), kephalē (head), and artos (bread), referring to the use of the pith to make food. They are, in evolutionary terms, some of the most primitive living gymnosperms. All the species are endangered, some critically, due to their exploitation by collectors and traditional medicine gatherers. The whole genus is listed under CITES Appendix I which prohibits international trade in specimens of these species except for certain non-commercial motives, such as scientific research. Several of the species possess stout trunks. In E. cycadifolius, the main trunks are up to 10 feet (3.0 m) high, and several of them may be united at a base where a former main trunk once grew. The persistent, pinnate leaves are arranged in a terminal spreading crown, or ascending. The rigid leaflets are variously spiny or incised along their margins. The leaflets have a number of parallel veins and no central vein. Male cones are elongated, and three or four may appear at a time. Female cones are borne singly, or up to three at a time, and may weigh up to 60 pounds (27 kg). In some species, male cones with ripe pollen emit a nauseating odour. When the pollen has been shed and the males cones decay, a strong odour of acetic acid has also been noted. Colonies of the cyanobacterium Nostoc punctiforme occur in apparent symbiosis inside the root tissue, while the rootlets produce root tubercles at ground level which harbour a mycorrhizal fungus of uncertain function, which is however suspected to facilitate the capturing of nitrogen from the air.