ENCEPHALARTOS TEGULANEUS SUBSP. POWYSII (ZAMIACEAE): A NEW CYCAD IN CENTRAL KENYABeatrice W. MiringuEast African Herbarium, National Museums of Kenya,P.O. Box 45166, Nairobi, Kenyaplants@africaonline.co.ke⟨sup⟩1⟨/sup⟩Henk BeentjeRoyal Botanic Gardens Kew,Richmond, Surrey TW9 3AE, U.Kh.beentje@rbgkew.org.ukABSTRACTA new cycad taxon, Encephalartos tegulaneus subsp. powysii, is described from Central Kenya. Taxonomic characteristics unique to this taxon in relation to the other subspecies are discussed. Its habitat preference, population and conservation status are also discussed.INTRODUCTIONThis taxon was first observed by a local administration officer in the 1950s but remained unknown to the scientific community until 1989, when one of us made the first incomplete collections. It took until 1996 before our collections were complete enough to allow a description. The taxon is named after Gilfrid Powys, a former District Officer of the area and avid plantsman, who took the second author up to the hill to show him the plants.While there are considerable similarities with Encephalartos tegulaneus Melville sensu stricto, the difference in leaflet and male cone structure warrant, in our opinion, subspecific status. The description of this population means a considerable range extension for the species as a whole.DESCRIPTIONEncephalartos tegulaneus Melville subsp. powysii Miringu & Beentje subsp. nov. a typo foliorum margine revoluto, dentatiore, dentibus conspicuis, microsporophyllis deflexioribus, e basi fertilibus, dorso uniangulus megastrobilo aurantiaco-brunneo differt. Typus: Kenya, Meru District, 23 Nov. 1995, Miringu 1 (holotypus EA, isotypus K) (figure 1).⟨sup⟩1⟨/sup⟩ Miami University, Institute of Environmental Sciences, 102 Boyd Hall, Oxford, Ohio 45056, USA, miringbw@po.muohio.eduTree up to 8 m tall, solitary or clustered with up to five trunks.Trunk erect or procumbent, unbranched or rarely with basal branching, 34-60 cm across at breast height, covered with rhomboidal pale brown scars 9.5 cm wide and 4 cm high, which become indistinct towards the base of the trunk.Figure 1 Encephalartos tegulaneus subsp. powysii, A-proximal leaf section, B-middle section, C-distal part, D-microsporophyll abaxial surface, E-female cone scale abaxial, F-female cone scale, tenninal facet, G-seed. All drawn from the type collection by Henk Beentje.Leaves 48-59 per trunk, suberect to spreading with some older leaves marcescent, 2-3.6 m long and 40-60 cm wide, pale green and white-pilose when young, glabrous when mature; petiole absent; rachis 280-290 cm long, proximally slightly pilose, 5-8 cm across and thick, glabrous between the leaflets; leaflets opposite or alternate, arranged at an angle of 180° between opposing rows, in 65-95 pairs inserted on the adaxial side of the rachis, proximal leaflets gradually reduced to prickles towards the base of the leaf, 2-4 cm apart in mid-leaf, overlapping, narrowly elliptic, ± straight but slightly falcate near apex, 18-31 cm long, 2.5-3.3 cm wide, proximal margins with (2-)3-4(-5) evenly spaced teeth, on the distal margin with (1-)2-3 teeth crowded near the base of the leaflet and 1 further towards the apex, the margins slightly revolute but the teeth clearly visible; distal leaflets decreasing in size, the terminal pair about 10 cm long and 0.8 cm wide. Cataphylls (scale leaves) confined to apex of trunk, c. 60, narrowly triangular, 8-19 cm long, to 2 cm wide, attenuate, coriaceous, pale brown-tomentose.Megastrobili 1-3(-4) per trunk, apparently sessile but with peduncle 6-16 cm long and 7-9 cm in diameter, hidden among the cataphylls; cones cylindrical or ellipsoid, 42-68 cm long, 16-22 cm in diameter, apricot orange; megasporophylls (cone scales) with pedicel acutely angled and 3 cm long, glabrous, the angle bulla/pedicel ± 60 degrees, the bulla 55 mm wide, 28-30 mm high, projecting 20-25 mm, the terminal face ± central and 1/2 to 1/3 of the horizontal diameter of the bulla, terminal facet smooth and slightly concave or flat, other facets rugose to tuberculate at the margins, the tubercles flattened and triangular, 1-4 mm long.Microstrobili (1-)3-5 per trunk, stalked with peduncles 11-22 cm long and 4-4.5(-9) cm thick, cylindrical or narrowly ovoid, 40-52 cm long, 9-12 cm in diameter, orange- yellow; bracts similar to those of megastrobili; median microsphorophylls spreading and angled, 38-44 mm long, 21-24 mm wide, 5-7 mm thick, bulla 8-9 mm wide, 5-6 mm high, projecting for up to 2 mm, smooth, glabrous, terminal facet slightly raised and about 1/3 the horizontal diameter of the bulla.Seeds covered with orange to mandarin-red sarcotesta, angled-obovoid, 30-43 mm long, 18- 30 mm in diameter, with the sarcotesta removed 28-36 mm long, 16-24 mm in diameter.AFFINITIESE. tegulaneus subsp. powysii resembles E. tegulaneus subsp. tegulaneus in many characters but differs in the number and position of spines on the leaflet margins. In both taxa the leaflet margins are revolute, but in subsp. tegulaneus this causes the teeth to be hidden, while in subsp. powysii they are pronounced. The number of teeth/spines also differs: subsp. tegulaneus has 1-2 teeth on the proximal leaflet edge (Melville, 1957, 1958; Faden & Beentje, 1989), while subsp. powysii has (2-)3-4(-5): subsp. tegulaneus has 0-2 teeth on the distal leaflets margin with one near the middle and one near the apex, while subsp. powysii has (1-)2-3 basal ones and 1 higher up. The female bulla pedicel has 4 sharp angles, and while the peduncle is described as irregularly dentate in subsp. tegulaneus (Goode, 1989), this is certainly not the case in all specimens of the latter. The colour of the female cone is orange-brown, not yellow as in subsp. tegulaneus, and the male cones scales are more deflexed than in the latter species.The male cone scales in subsp. powysii have a much shorter sterile lower surface (5-7 mm), with a single angle and are fertile right down to their very base, while those of subsp. tegulaneus have a longer sterile part (10-15 mm long), with two angles enclosing a facet, and have a sterile part near their base of 5-6 mm long.The presence of the groove on the rachis between the leaflets in subsp. tegulaneus mentioned in various descriptions (Melville, 1957, 1958) does not hold true for the type of the taxon. We believe this might be an artifact.One of the referees suggested that specific status would be preferable for this taxon. This was our original idea as well, but upon thorough study of the material we decided that the differences between E. tegulaneus sensu stricto and the new taxon were less than those with other species (table 1), and hence we decided on this status. There is a precedent with a Nigerian subspecies described by L. Newton.Table 1. Taxonomic similarities and differences between subsp. tegulaneus and subsp. powysiiCharacteristicSimilaritiesDifferencessubsp. powysiisubsp. tegulaneusMarginsRevoluteTeeth hiddenTeeth exposedSpinesPresent2-51-2ProximalPresent1 near the apex1 near the apexDistalPresent1-3, basal0-2, near the base, 1 at the middleFemale coneSame sizeOrange-brownYellowFemale bullaSame sizePedicel with 4 sharp anglesIrregularMale coneLess deflexedDeflexedMale cone scalesShort (5-7 mm)Longer (10-15 mm)Single angled2-angled, enclosing a facetFertile to baseSterile part of 5-6 mm near baseGEOGRAPHICAL DISTRIBUTIONOnly known from a single hill in Meru District (K 4). To protect this taxon from collection from the wild, we have deliberately left out the specific locality details in this publication.HABITAT PREFERENCEThe subspecies occurs in rocky sites in dense bushland/thicket with Commiphora sp., Ochna sp. and Teclea sp. where it is locally common. It is less common in dry forest with Drypetes natalensis, Croton megalocarpus, Rawsonia lucida, Milletia leucantha, Garcinia volkensii, Uvariodendron anisatum, Strychnos henningsii. The highest density is found in the altitudinal range of 1,600 m to 1,800 m.POPULATION AND CONSERVATION STATUSSub-populations are found on different parts of the hill at about 1,600-1,800 m altitude. The whole population is estimated to be 500-600 mature individuals. A preliminary sex count done on one of the sub-populations showed a sex distribution of 2/1, male/female.By the IUCN category (1994) this taxon is 'Critically Endangered', as it is occupying an area of less than 10 km⟨sup⟩2⟨/sup⟩. Although this species occurs in a forest reserve, the neighbouring human communities use the forest as a source of fuelwood and construction materials. Hunting of small mammals and honey gathering are other human activities going on in the forest, and some illegal collecting of seedlings by cycad amateurs has already taken place.ACKNOWLEDGEMENTMany thanks to Gilfrid Powys for having reported the existence of this taxon to the scientific community and for taking the second author to see the population. We would also like to thank Prof. Len Newton for his help in drawing up the description of the cones and cone scales. We are most thankful to ODA/NMK Plant Conservation Programme for financial support and providing equipment during the field surveys. Many thanks to the staff of the East African Herbarium, and to the local administrators and communities for their hospitality during the surveys. Two anonymous reviewers are thanked for helpful comments and suggestions.REFERENCESFaden, R.B. & H.J. Beentje (1989). Encephalartos kisambo, a new cycad from Kenya, with a note on E. tegulaneus. Utafiti 2(1): 7-10.Goode D. (1989). Cycads of Africa. Struik, Winchester.Melville, R. (1957). Encephalartos in Central Africa. Kew Bulletin 12: 237-257.Melville, R. (1958). Gymnospermae. In W.B. Turrill & E. Milne-Redhead (eds), Flora of Tropical East Africa. Crown Agents, London.IUCN (1994). IUCN Red list categories. IUCN Species Survival Commission, Gland.