P. Vorster

Phylogenetic relationships, based on allozyme data, between six cycad taxa indigenous to South Africa

Phylogenetic relationships between Encephaiartos altensteinii Lehmann, E. friderici-guilielmii Lehmann, E. lehmannii Lehmann, E. natalensis Dyer & Verdoorn, E. transvenosus Stapf & Burtt Davy and E. villosus Lemaire were studied, using Cycas revoluta Thunberg as outgroup. Three continuous and one discontinuous buffer systems were used and gene products of 21 enzyme coding loci were examined by horizontal starch gel-electrophoresis. A biochemical key, based on fixed allele differences, is presented. Fixed allele differences at one locus between E. altensteinii and E. natalensis may confirm that these species do not share the same gene pool. However, the genetic distance is the least (0.042) between these two species, compared to the mean genetic distance value of 0.222 for the other ingroup taxa. The results are discussed with reference to affinities based on morphology and distribution.

Encephalartos senticosus (Zamiaceae): A new species from northern KwaZulu-Natal and Swaziland

Encephalartos senticosus is described from the Lebombo Range of northern KwaZulu-Natal and Swaziland. Vegetatively it is similar to E. lebomboensis Verdoorn with which it was previously confused, but differs in its male cones being stalked instead of sessile with the exposed faces of the microsporophylls drawn out into drooping beaks instead of raised pyramidally, and the megasporophylls with exposed faces pyramidally raised instead of more or less flat.

Encephalartos msinganus (Zamiaceae): A new species from KwaZulu-Natal

Encephalartos msinganus is described from the Tugela Ferry area in northern KwaZulu-Natal. It resembles E. natalensis R.A. Dyer & Verdoorn in its similar male cones and especially its verrucose female cones, but differs in its much narrower pinnae (16–20 versus 25–45xa0mm). It resembles E. senticosus Vorster vegetatively and in its similar male cones, but differs in the verrucose instead of smooth exposed faces of the megasporophylls.

Encephalartos aplanatus (Zamiaceae): a new species from Swaziland

Encephalartos aplanatus is described as new from north-eastern Swaziland. It resembles E. villosus Lem. in its acaulescent habit, small number of long and arched leaves, proximal leaflets gradually reduced to prickles, and virtually identical cones, but differs in being altogether larger with longer leaves which are often shortly petiolate instead of sessile, with leaflets larger, more dentate, and with their margins out of plane or somewhat undulate rather than flat.

Encephalartos venetus (Zamiaceae): A new species from the Northern Province

Encephalartos venetus is described from the Northern Province. It resembles E. cupidus R.A. Dyer In its glaucous foliage, strongly dentate sub-adult-stage leaflets, glaucous green cones, and the morphology of the micro- and mega-sporophylls, but differs In being a much larger and arborescent, instead of a more or less acaulescent plant, with entire Instead of conspicuously dentate adult-stage leaflets.

Encephalartos brevifoliolatus (Zamiaceae): A new species from the Northern Province

Encephalartos brevifoliolatus is described from the Northern Province. It resembles E. laevifolius Stapf & Burtt-Davy in having practically identical male cones, slender but rigid and spineless petioles with a whitish felt-like indumentum when young, and relatively narrow and entire leaflets which are abaxially finely ribbed. It differs from E. laevifolius and related species in its conspicuously wider and shorter leaflets with revolute margins.

Using the WORLDMAP PC program for measuring biodiversity in order to choose prioritized conservation areas in southern Africa

The various measures of biodiversity available on the W orldmap PC-program are discussed. Data on Mariscus Vahl (Cyperaceae) are used to illustrate these measures as well as to elucidate the choosing of prioritized conservation areas in southern Africa.

Encephalartos successibus (Zamiaceae): A new species from Uganda

Encephalartos successibus , a new species from Uganda, is described, illustrated and circumscribed in terms of other tropical African arborescent species of Encephalartos , It is a large arborescent plant, with mostly non-overlapping leaflets, The strobili are green and glabrous; the megastrobilus is ovoid, shortly pedunculate but with peduncle buried in cataphylls so that the megastrobilus appears to be sessile, with the exposed faces of the megasporophylls more or less smooth; the microstrobili emerge in succession, being narrowly ovoid, long-pedunculate, with the exposed faces of the microsporophylls smooth.