Bothalia - African Biodiversity and Conservation

Online ISSN: 0006-8241
Publications
Chapter
Trees, shrubs, climbers, lianas or annual to perennial herbs; L nearly always alternate, often plnnate or plnnately 3-foliolate or digitately compound, occasionally 1-foliolate; stipules usually present, various; tendrils sometimes present (esp. in the tribes Cercideae and Vicieae); Inf splkes, racemes, panicles or heads; Fl variable, small to medium to large, mostly bisexual, actinomorphic or zygomorphic; Sep in actinomorphic Fl (3-) 4 - 5 (-6), connate or free, in zygomorphic Fl (4-) 5, free or connate into a toothed or lobed Cal; Pet in actinomorphic Fl as many as Sep, in zygomorphic Fl 5 (or fewer by abortion); St inserted with the Pet at the rim of the Rec, usually 10 but sometimes fewer or more; Fil free or variously connate; Anth 2-thecous, generally opening by longitudinal slits; Ov almost always superior, 1-locular, with 1 to many ovules; Sty and Sti simple; Fr nearly always a dry legume (pod), usually dehiscing into 2 valves, less often dehiscing only along the upper suture or splitting transversely into 1-seeded segments, or indehiscent; Se various, without or with very little endosperm.
 
-Soil properties for communities (mean with standard deviation in brackets)
Article
Community structure and composition of the coastal fynbos and rocky headland plant communities south of George, southern Cape, were studied. Vegetation was analysed using standard sampling procedures of the floristic-sociological approach of Braun-Blanquet. The releve data were subject to TWINSPAN-based divisive classification, and ordinated by Principal Coordinates Analysis with the aim to identify vegetation coenocline subsequently interpreted in terms of underlying environmental gradients. Most of the sampled vegetation was classified as coastal fynbos. The Leucadendron salignum-Tetraria cuspidata Fynbos Community was found to occupy sheltered habitats, whereas the Relhania calycina-Passerina vulgaris Fynbos Community was found in exposed habitats. The other two communities characterise strongly exposed rocky headlands. The Pterocelastrus tricuspidatus - Ruschia tenella Community is wind-sheared scrub, and the Gazania rigens - Limonium scabrum Rocky Headland Community is a loose-canopy, low-grown herbland, characterised by the occurrence of partly salt-tolerant and succulent herbs. The ordination of the fynbos communities revealed a horseshoe structure allowing a direct recognition of a coenocline spanning two fynbos communities along the Axis 1 interpreted in terms of exposure to wind and salt spray. A considerable amount of alien plant infestation was also present. This appears to be the largest threat to the continued existence of this coastal fynbos.
 
Article
Euclea sekhukhuniensis Retief, Siebert & A.E.van Wyk, a new species with a restricted range in Sekhukhuneland, South Africa, is described, illustrated and compared with other members of the genus. It is a gregarious geoxylic suffrutex forming large, much-branched colonies. The species is closely related to the small tree/shrub E. linearis Zeyh. ex Hiern from which it can be distinguished by its larger fruits, broader leaves and exclusively suffrutex growth form. Geographical range and habitat preference also differ between the two taxa. E. sekhukhuniensis is endemic to the Sekhukhuneland Centre of Plant Endemism, where it is confined to the calcareous, heavy-metal soils of the Steelpoort River Valley.
 
Article
The family of the Apocynaceae is usually subdivided into two subfamilies, the Plumerioideae with the type genus Plumeria from tropical America, and the Apocynoideae, often named Echitoideae, with the type genus Apocynum from North America. These subfamilies show two characters which are more or less diagnostic for all members. However, since the taxonomists have built up the present scheme of the Apocynaceae, phytochemists have observed that many plants belonging to the Plumerioideae contain alkaloids, and that many representatives of the Apocynoideae contain glycosides. Some of the alkaloids, e.g. those of Catharanthus, Rauvolfia and Voacanga, and some of the glycosides, e.g. those of Funtumia and Strophanthus are of medicinal interest. In the present paper, the arrangement of the genera within the Plumerioideae is mainly that of Pichon (1949, 1950, 1953a, 1953b). He subdivided all tribes, except the Tabernaemontaneae, into subtribes, which is an excellent concept according to the present author. The latter, however, does not always agree with the delimitation of the genera. For instance, he does not accept the sinking of Acokanthera under Carissa, especially as the plants belonging to these genera show great differences in architecture (Hallé & Oldeman 1970; Hallé, Oldeman & Tomlinson, 1978), but he sinks several genera maintained by Pichon, e.g. Ervatamia under Tabernaemontana (1976).
 
Article
Copyright: 1993 National Botanical Institute There are cape Asteraceae species that have conspicuous dark markings on their ray florets. Such markings are usually interpreted as guides of various sorts. It is thus suggested that the dark raised marks on the ray florets of Gorteria diffusa thumb mimicked herbivorous beetles burrowing head down in the inflorescences. It is also noted that this species appeared to have few beetle visitors and to suffer less herbivory than other Asteraceae (such as an Arctotis sp.) growing nearby. The marks repel the beetles. However in this review of plant mimicry worldwide, it is considered an exceptionally intriguing example of Batesian mimicry. Despite the fact there still appears to be a dearth of information on the interaction between beetle-daisies and beetles, hence the purpose of this note is to extend the concept of beetle-daisies and to test Hutchinson’s hypothesis.
 
-Carte. schdmatique des principales zones climatiques. et de végétation de l'Afrique au nord de I'équateur. (Sources: entre I'équateur et la zone sahélienne, d'aprks la carte de végétation de 'I'AETFAT, 1958; pour le Sahara, les traits pleins sont d'eprbs Quezel, 1965 et les pointillés sont une estimation, Maley, 1981). Pour les fi
Article
LATE QUATERNARY HISTORY OF VEGETATION AND CLIMATE OF TROPICAL NORTH AFRICAThe critical examination o f available pollen data from the vegetation of the Sahara allows one to conclude that this vegetation has gone through but few qualitative changes during the last twenty thousand years. In particular, one notices an extension in the Sahara of tropical Sahel taxa about the middle of Holocene. Quantitatively, some pollen and geological data converge to Show that the Saharian plains were extremely arid between about 20 000 and 15 000 years BP and that on the mountains the vegetation became very sparse. A new colonization began on the mountains about 15 000 years ago.The pollen study of Holocene sediments from the central part o f the Chad basin was done in the Tjéri station. The results of this study exhibit a major change near 7 000 years BP, characterized in the Sahel zone by a dramatic extension o f arboreal taxa until about 5 000 years BP, probably corresponding to northward extension of the sahel savanna. One important change took place also at the same time in the wet north tropical zone where, between about 7 000 and 4 000 years BP, there occurred an extension of taxa growing presently on the well-leached soils of interfluves.Such a change near 7 000 years BP also appears in the available stratigraphical, sedimentological and pedological data from tropical north Africa. One observes particularly that, between 15 000 and 7 000 years BP, the
 
Article
Patterns in species richness of 23 small, isolated forests on the inland mountains of the southern Cape were studied. Species richness of woody plants and vines of the Kouga-Baviaanskloof Forests was higher than in the western mountain complexes, where species richness in the more southern Rooiberg and Kamanassie Mountains was higher than in the Swartberg range. The Rooiberg, a dry mountain with small forests far away from the coastal source area, had more species than, and contained many species which are absent from, the larger, moister forests of the Kamanassie which are closest to the coastal source areas. Neither altitude nor distance from the source area, the forests south of the coastal mountains, nor long-distance dispersal, adequately explained the variation in species richness. The variations are best explained in terms of dispersal corridors along the Gouritz and Gamtoos River systems which connect the coastal forests with the inland mountains. The distribution patterns of four species groups in relation to the geomorphological history of the two river systems provide relative dates for the expansion and contraction of temperate forest, subtropical forest and subtropical transitional thicket in the southern Cape.
 
Article
The Cape of Good Hope Nature Reserve, 7 750 ha in extent, occupies the southern end of the Cape Peninsula. Geologically, it is composed of sandstone beds of the Table Mountain Group of the Cape Supergroup. Topographically, it comprises an interior plateau bounded partly by hills and mountains which reach 360 m on the False Bay coast. Two structural formations, fynbos and broadleaved scrub, are recognized. Within fynbos, the two floristic categories, Inland and Coast Fynbos, reflect the two major soil types present. The flora of the Reserve, with 1 060 species (35% monocots, 65% dicots) comprises 40% of the flora of the Cape Peninsula. About 40 species are either endemic or rare and endangered to varying degrees. Alien woody plants that have invaded the veld over the past half-century are presenting a serious and costly management problem.
 
Article
The vegetation of the Nylsvley Nature Reserve in the Transvaal Mixed Bushveld is classified hierarchically by the Braun-Blanquet method of vegetation survey. The vegetation is seasonal grassland and deciduous savanna with four floristically distinct major groups of plant communities : Grasslands and broad-leaved savannas on non-calcareous sandy soils on elevated sandstone and felsite areas; microphyllous thorn savannas on calcareous, clayey, bottomland alluvial soils and termitaria thickets; grassland and thorn savanna on calcareous self-mulching vertic soils; and secondary communities on long abandoned native settlements and recently ploughed land. Seven primary communities with 12 community variations and four subvaria-tions, and three secondary communities are described on the basis of 216 releves. The survey was carried out at two levels of detail, the ecosystem study area in the broad-leaved savanna being surveyed in more detail, floristically and structurally, than the rest of the Reserve.
 
Article
TWO NEW TAXA AND A NEW COMBINATION IN SOUTHERN AFRICAN PTERIDOPHYTA
 
Article
Another two new endemic species of the subgenus Riccia. section Riccia. group ‘Squamatae , are described: R. montana and R alboporosa. The distribution of R montana is apparently restricted to high altitudes in the Drakensberg and Witteberg Mountain ranges. The species is characterized by ligulate branches, finely spongy dorsal surface and hyaline to white, calcium-encrusted scales. R alboporosa is found in Namaqualand. but it is rare It can be recognized by the distinctly porous appearance of the dorsal surface due to the presence of large. ± regularly spaced air pores, which are encircled by six or seven radially arranged, wedge-shaped cells that become white on drying, hence the specific epithet.
 
Article
Fossombronia zuurbergensis Perold, sp. nov. from Eastern Cape is described. It is distinguished by having leaves and pseudoperianths with markedly dentate margins; the spore ornamentation on the distal face consists of ridges which can be quite variable, although, at least some of them run parallel to each other in straight or curved, short or long ridges, others occurring at right angles to the former. New records for F. capensis var. capensis and F. crispa are reported for Eastern Cape.
 
Article
Three species of Tetradenia are recognized in the Malagasy Republic: T. fruticosa Benth.. T. goudotii Briq. (= T. hildebrandtii Briq.) and the newly described T. nervosa Codd.
 
Article
Riccia hantamensis, a new species from the Hantams Mountain, District Calvinia, is described. It is clearly related to R. alatospora, but is a much larger plant. Like other species with a dorsal epithelium of free-standing cell pillars, it belongs to section Pilifer Volk. R. alatospora, originally only known from Platklip, Stellenbosch (Volk & Perold 1985), is now also recorded from Carolusberg, Hester Malan Reserve, Namaqualand.
 
Article
The occurrence of flower dimorphism in the genus Lotononis (DC.) Eckl. & Zeyh. is reported for the first time. Cleistogamous flowers have been observed in 12 species from four different groups of the sections Leptis (Eckl. & Zeyh.) Benth. and Oxydium Benth. Morphological differences between chasmogamous and cleistogamous flowers are discussed and illustrated. The phenomenon of flower dimorphism appears to be of limited taxonomic value but nevertheless supports the idea of an affinity between the L. laxa, L. pungens and L. leptoloba groups. Two recently discovered new species of the L. leptoloba and L. calycina groups, L. venosa B-E. van Wyk and L. acuticarpa B-E. van Wyk, are described.
 
Article
The distributions, endemism and tribal affiliations o f taxa in the family Asteraceae in southern Africa are updated. New ombinations and newly described species are added to the previously published lists.
 
Article
A historical account is given of the confusion caused by the application of the name R. concava to various taxa. A new description of the species as understood by the author is given and a comparison made with related species. Its distribution and ecology are noted.
 
Article
A description of Riccia albomarginata Bisch. ex Krauss, augmented with the aid of new collections which most closely match the relevant fragments of the type material, is presented. The type collection comprises two species. The fragments that I consider to be in closest agreement with Krauss’s protologue are selected as lectotype. As far as could be established the rest of the type material is probably referable to R. concava Bisch. As previously mentioned by Perold (1989b), Sim (1926) and subsequent authors had applied the name * R. albomarginata' to a different taxon. This taxon, R. albomarginata auct. non Bisch., is now described and illustrated as R. simii, sp. nov. Its distribution and ecology are also noted.
 
Article
Species in section Pilifer Volk (1983) are often very difficult to identify (Perold 1990b). Most of them require close examination of the dorsal cell pillars in reasonably fresh collections, as these cells can seldom be reconstituted in long dried material.The three species, R elongata. R ampullacea and R trachyglossum, here described as new, have been maintained in cultures for lengthy periods, during which their dorsal cells were studied. The spore ornamentation was also quite useful in separating these species. R elongata is known from eastern Transvaal, R. ampullacea from the Witteberg Mountains of the eastern Cape Province and the Drakensberg Mountains of Lesotho and Natal, and R. trachyglossum is so far known only from (he highlands of Lesotho.
 
Article
The handling of controversial Proposal 1584 to conserve the name Acacia with a conserved type for the Australian acacias during the Nomenclature Section meeting at the 17th International Botanical Congress (Vienna) in 2005 is reviewed. Through a simple majority vote, this Section adopted rules requiring a 60% majority of votes to approve any proposal to modify the International Code of Botanical Nomenclature and a simple majority to approve all other motions; motions not receiving the required majority were to be rejected. However, for the motion addressing Proposal 1584, 45.1 % voted to conserve the type of the name Acacia for Australian acacias, and 54.9% voted to retain the current African type for the name Acacia. Even though this motion failed to get a 60% majority either way as required by the Section's own rules, Section officials have concluded that the name Acacia is to be conserved for Australian acacias. Treating a motion as approved, even though it received only minority support, also violates the fundamental principle of standard parliamentary procedure - the right of the majority to approve proposals. For Acacia to be formally conserved, the Nomenclature Section needed to approve a motion addressing Proposal 1584 with a majority vote, and this never happened in Vienna. Recommendations are made on how this process might be improved.
 
Article
Another three new species of Riccia in section Pilifer Volk are described from Namaqualand, namely R. furfuracea, R vitrea and R. namaquensis. There are certainly more undescribed species present in that region, but species from there are often very difficult to distinguish: almost all have hyaline scales, the free-standing dorsal cell pillars need to be examined in living plants and the spore ornamentation is quite variable.
 
Continued 
Article
Anton Rehmann undertook two collecting expeditions in South Africa, in 1875-77 and 1879-80, during which he collected over 9 000 numbers. The latter journey took him as far north as the Houtbosch in Transvaal, where he was the first to make an extensive collection. A brief account is given of his life and his itineraries in South Africa with details, as far as can be ascertained, of his collecting localities.
 
Article
Emil Holub was a nineteenth century, Austro-Hungarian Czech, medical doctor with wide-ranging interests in ethnography and the natural sciences. During visits to southern Africa in the 1870s, he meticulously recorded everything that he encountered. Amongst his vast collection of artifacts, natural history specimens and notes were several sketches of fungi. These illustrations are reproduced here to document this valuable historical knowledge, tentatively identifying them in the context of the habitats through which Holub travelled.
 
-Thode's main Drakensberg expeditions
Article
An account is given o f the life o f Hans Justus Thode (1859-1932) from the time of his arrival in Cape Town in 1885 or 1886 until his death in Durban in 1932. Thode was the pioneer plant collector of the Natal Drakensberg, but also collected wider afield in all four provinces of the Republic. His contributions to South African botany are assessed.
 
Article
The history of the Natal Herbarium is described from its inception in 1882 to 1982, the year of its centenary. Its history is inextricably linked with that of the Durban Botanic Gardens which started as an Agricultural Garden in 1848, and the Durban Botanic Station. The roles played by various curators and officers-in-charge, especially John Medley Wood, who held office for 32 years and did much to put the Herbarium on the botanical map, are emphasized.
 
Article
R. pulveracea, specimens of which were collected by Duthie and tentatively referred to R concava by her. is described here, following the recent collection of fresh material. This species is distinguished from other members of section Pilifer (Volk 1983) by low. generally two-celled, free-standing dorsal cell pillars, which when dry, appear powdery, hence the specific epithet. R bicolorata. section Riccia. group 'Squamatae' occurs in the Cape but is rarely collected, and is characterized by bicoloured scales, of which the wide hyaline margins are heavily encrusted with calcium deposits. It is somewhat similar to R. pottsiana, but larger, and its scales are not so regularly arranged.
 
Article
A brief biographical sketch is given of the Rev. C.T. Hahn, an English-born, Oxford-educated Anglican missionary in Zululand who painted some 235 watercolours of Natal flora between 1908 and 1913. Hahn (who later changed his name to Headley) was one of the most productive of the early botanical illustrators in Natal but as a collection of his paintings has only recently been discovered, his work has until hitherto remained unknown.
 
Top-cited authors
John C Manning
  • South African National Biodiversity Institute
Johan J. Spies
  • University of the Free State
Gideon F. Smith
  • Nelson Mandela University
M. J. A. Werger
Brian van Wilgen
  • Stellenbosch University