bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytogenetic studies in the <i>Eragrostis curvula</i> Complex
Authors: Vorster T. B. 
Published: July 2015

Cytogenetic studies were undertaken in the Eragrostis curvula Complex. Three plants were studied at each of 16 collecting points. The overall morphology and embryo sac development of all plants were evaluated, while the chromosome number and microsporogenesis of some of the plants were also studied. The collecting points were chosen so ^s to represent a variable environment extending from the bushveld to the highveld regions of the Transvaal. It was found that the embryo sac development of the plants from the bush\eld and the highveld were, for all practical purposes, obligate diplosporic apomicts, whereas the transition area contained obligate as well as facultative diplosporic apomicts. The same pattern also held as far as the plant morphology, chromosome number and microsporogenesis were concerned.
The pollination of <i>Canavalia virosa</i> by Xylocopid and Magachilid bees
Authors: Stirton C. H. 
Published: July 2015

The floral morphology of Canavalia virosa (Roxb). Wight Arn. is discussed in relation to pollination by Xylocopa flavorufa De Greer and Megachile combusta Sm. It was found that the relationship between size of flower and bee influenced the type of pollinating strategy and its success. Bees smaller than M. combusta proved ineffective pollinators.
Freshwater algae of Southern Africa. IV. Some Micrasteriae from Rhodesia, including a new species
Authors: Claasen M. Isabella 
Published: July 2015

Micrasterias ambadiensis (Gronblad Scott) Thomasson, M. crux-melitensis (Ehrenberg) Hassall forma minor Turner, M. decemdentata (Nageli) Archer, M. pinnatifida (Kutzing) Ralfs var. incudiformis West West, M. radiata Hassall var. brasiliensis Gronblad sensu lato, and M. tropica Nordstedt var. tropica are discussed. A new species, M. schweickerdtii Claassen, is described.
Automatic classification of the highveld grassland of Lichtenburg, south-western Transvaal*
Authors: Morris J. W. 
Published: July 2015

A qualitative, semi-detailed plant ecological study o f the area between 25° 54' and 26° 22' E and 26° 00' and 26° 20' S, situated around the town o f Lichtenburg in the south-western Transvaal, Sou.h Africa, is reported. Mean annual temperature o f the study area is 17 °C and annual rainfall is about 600 mm. A basic difference is recognised between the Bankenveld Land System and the CT Grassland Land System. The former is underlain by dolomite with lithosolic soils, Bankenveld vegetation and cattle ranching as the chief iar.d-use, whereas the latter is underlain by granite, Ventersdorp lavas, Dwyka tillite and surface limestone with Snorrocks, Mangano and Lichtenburg series soils, Cymbopogon-Themeda Veld vegetation and extensive cultivation of maize as the chief land-use. One hundred and ten 16 m2 quadrats were placed within each Land System by means of a stratified-random strategy. Of the 247 species encountered, nearly 100 occurred in less than six quadrats. Themeda triandra, Aristida congesta, Elionurus argenteus, Anthospermum rigidum and Justicia anagaloides were common throughout. Two association analyses were carried out and 15 final groups were interpreted out of a total of 21 groups.
A preliminary account of aerial plant biomass in fynbos communities of the Mediterranean-type climate zone of the Cape Province
Authors: Kruger F. J. 
Published: July 2015

Aerial plant biomass has been sampled by harvesting on several sites in fynbos communities of the south­western Cape Province. Biomass in stands of about two years old ranged from about 2 200 kg per ha to about 7 500 kg per ha. Mature stands comprised about 11 000 to 15 000 kg per ha in heaths and 15 000 to 26 000 kg per ha in sclerophyllous scrub. The data indicate a maximum annual growth rate of 1 000 to 4 000 kg per ha early in the development of a stand, but growth rates appear to decline rapidly as communities age. Young stands are dominated by hemicryptophytes, which comprise about 2 000 to 6 000 kg per ha, or about 60 to 75 per cent of the biomass in stands of about four years old. Shrubs become prominent later, but the hemicryptophytes persist. The data indicate that the biomass, growth rates and the shape of the growth curves of fynbos communities are on the whole similar to those of analogous vegetation in other zones of mediterranean type climate. However, there are important structural differences in that analogues of the northern hemisphere (garrigue, chaparral) do not have a significant component of persistent hemicrytophytes. Although Australian heath communities do have this feature, the hemicryptophytes are not as prominent as in fynbos.
Southern African Loranthaceae and Viscaceae: new taxa * and new combinations
Authors: Wiens Delbert 
Published: July 2015

Two new genera are named: Pedistylis Wiens with the type species P. galpinii (Schinz ex Sprague) Wiens and Vanwykia Wiens with the type species V. remota (Bak. Sprague) Wiens. Three new species and one new subspecies are described: Plicosepalus amplexicaulis Wiens, Tapinanthus crassifolius Wiens, Viscum oreophilum Wiens, and V. capense L.f. subsp. hoolei Wiens. The following nomenclatural changes are made: Actinanthella wyliei (Sprague) Wiens, Tapinanthus forbesii (Sprague) Wiens, T. leendertziae (Sprague) Wiens, T. kraussianus (Meisn.) Danser subsp. transvaalensis (Sprague) Wiens, T. natalitius (Meisn.) Danser subsp. zeyheri (Harv.) Wiens, Tieghemia bolusii (Sprague) Wiens and T. rogersii (Sprague ex Burtt Davy) Wiens.
Notes on the vegetation of the Sani Pass area of the southern Drakensberg
Authors: Killick D. J. B. 
Published: July 2015

The vegetation of the Sani Pass area of the southern Drakensberg between 2 600-3 260 m is briefly described and illustrated. Air temperature and rainfall data are provided. A reference is made to the Themeda triandra Grassland occurring on the summit of the Drakensberg at Ngwangwana Pass (Thamatuwe Pass), some 30 km south of Sani Pass.
Gross vegetation changes in the dune area between Richards Bay and the Mfolozi River, 1937—1974
Authors: Weisser P. J. , Marques F. 
Published: July 2015

Marked changes in dune vegetation as shown on air photos taken in 1937 and 1974 are described and quantified. About fifty-five per cent of the study area changed from one mapping unit to another. The changes are due mainly to secondary successions e.g. from grassland to Acacia karroo Woodland and Acacia karroo Woodland to Secondary Dune Forest. They result from protection by the Department of Forestry, which is also responsible for extensive afforestation. It is estimated that under the existing favourable climatic conditions it takes some dune grassland only 25-60 years to develop to mature Acacia karroo Woodland and a further 30 to 150 years to proceed to Secondary Dune Forest.
Towards a structural-functional classification of fynbos: a comparison of methods
Authors: Linder P. , Campbell B. M. 
Published: July 2015

The need for a classification of the vegetation of the fynbos region is stressed. In the present work we have evaluated some structural-functional approaches that could be used to classify and describe fynbos. A priori and a posteriori approaches to classification are reviewed. The a posteriori approach appears to be superior.Test data derived from 21 plots from a range of fynbos types were used to test some methods of collecting and analysing structural-functional information for an a posteriori classification. With respect to data collection, no single method was superior. However, a major improvement on our methodology would be possible if the growth-form system used were to be extended. The classifications that were erected were produced by means of computer-based numerical methods. These methods are essential if large data sets are to be analysed. However, the structural-functional classifications produced by numerical methods should only be regarded as working hypotheses; refinement of the classifications should proceed by intuitive methods. We feel that the a posteriori approach, even though it has its problems, will provide a suitable methodology for an ecologically meaningful classification of fynbos vegetation.
Revision of <i>Melhania</i> in southern Africa
Authors: Verdoorn I. C. 
Published: July 2015

The 13 species of Melhania in southern Africa are revised. Among the problems resolved is a long-standing one concerning the identities of M. rehmannii Szyszyl. and M. griquensis H. Bol., the latter in its strict sense being relegated to synonymy o f the former.
The <i>Eriosema cordatum</i> complex. II. The <i>Eriosema cordatum</i> and E. nutans groups
Authors: Stirton C. H. 
Published: July 2015

The Eriosema cordatum E. Mey. complex is segregated into a number of species. E. cordatum E. Mey. is retained as a polymorphic species and two allied species, E. lucipetum C. H. Stirton and E. zuluense C. H. Stirton are described as new. Four additional species E. buchananii Bak. f. , E. nutans Schinz, E. psoraleoides (Lam.) G. Don and E. parviflorum E. Mey. are revised and excluded from the E. cordatum group.
Taxonomic studies in the Disinae. VI. A revision of the genus <i>Herschelia</i>
Authors: Linder H. P. 
Published: July 2015

The genus Herschelia (Disinae, Orchidaceae) is revised. Sixteen species, one subspecies and one variety are recognized. Two new species from tropical Africa (H. chimanimaniensis Linder and H. praecox Linder) and a new variety from the Cape Province H. lugens (H. Bol.) Kraenzl. var. nigrescens Linder are described. Three new combinations are made by transferring the two species of Forficaria and Disa sect. Microperistera (one species) to Herschelia. Thirteen species are illustrated, and the nomenclature and the available information about the habitats of the taxa are discussed. The species are grouped into two subgenera, one of which is further divided into two sections and four series. This classification is based on the putative phylogeny, as determined by the method devised by Wagner (1962).
CYPERACEAE: ECOLOGICAL ADAPTATIONS AND POSSIBLE CONVERGENCE IN <i>FICINIA ARENICOLA VAR.ERECTA</i> AND <i>MARISCUS DURUS</i>
Authors: Arnold T. H. , Voster P. J. 
Published: July 2015

ECOLOGICAL ADAPTATIONS AND POSSIBLE CONVERGENCE IN FICINIA ARENICOLA VAR.ERECTA AND MARISCUS DURUS
Leaf anatomy of the South African Danthonieae (Poaceae). IV. <i>Merxmuellera drakensbergensis</i> and <i>M. stereophylla</i>
Authors: Ellis R. P. 
Published: July 2015

The leaf blade anatomy of Merxmuellera drakensbergensis (Schweick.) Conert and M. stereophylla (J. G. Anders.) Conert is described and illustrated. These two closely related species have virtually identical leaf anatomy—both the leaf in section and the abaxial epidermis. The close anatomical resemblance between these two species raises doubts about their specific status. This is especially significant when compared with the considerable differences observed between the anatomical ‘forms’ recognized in M. disticha (Nees) Conert (Ellis, 1980) and M. stricta (Schrad.) Conert (Ellis, 1980a).
Plants used by the Tsonga people of Gazankulu
Authors: Liengme C. A. 
Published: July 2015

A study was undertaken in part of the Tsonga homeland, Gazankulu, to identify plants used by these people. A list of Tsonga plant names was extracted from a Tsonga-English dictionary and this was used as a basis for the study. The uses of almost 200 plants were recorded, including medicine, food, building materials, firewood, household utensils, implements, implement handles and toys. This information is presented in the form of an annotated list of the plants. This is followed by a discussion of some of the more important uses. Some of the aspects of Tsonga taxonomy are briefly discussed and illustrated with examples.
A brief account of coast vegetation near Port Elizabeth
Authors: Taylor H. C. , Morris J. W. 
Published: July 2015

The environment and vegetation of an area of coast north-east of Port Elizabeth, South Africa, are briefly described. Five major vegetation categories are recognized. These are: 1. Scaevola thunbergii Pioneer Vegetation of littoral dunes and Ficinia lateralis Sedgeland of calcrete gravel; 2. Olea exasperata Bush, Pterocelastrus tricuspidatus Bushclumps and Dune Woodland; 3. Sundays River Scrub; 4. Fynbos of calcrete areas; and 5. Themeda triandra Grassland. Invasion of the area by Acacia cyclops (Australian W'attle) is described. A recommendation for the conservation of the area as a nature reserve is made.
Monitoring <i>Phragmites</i> australis increases from 1937 to 1976 in the Siyai Lagoon (Natal, South Africa) by means of air photo interpretation
Authors: Weisser P. J. , Parsons R. J. 
Published: July 2015

The colonization o f the Siyai Lagoon on the north coast of Natal by Phragmites australis was studied by means of air photo interpretation. It was possible to locate and estimate P. australis areas for 1957 (0,74 ha), 1965 (1,65 ha), 1969 (1,93 ha) and 1976 (2,94 ha). Phragmites australis first inhabited the shores of the middle section o f the lagoon followed by rapid expansion in the lower section. The upper section was colonized only at its lower end by expansion from the middle section. It is suggested that P. australis was unsuccessful in this section because of competition by the Hibiscus tiliaceus—Barringtonia racemosa Lagoon Fringe Forest. This same community is shading out P. australis in some places. The notable increase in the rate of advance of land and littoral vegetation into the Siyai Lagoon was caused by sugar farming activities leading to erosion and sedimentation in the lagoon. A vegetation age gradient was observed from the upper section to the mouth region. The colonization of most of the Siyai Lagoon except the immediate mouth zone by P. australis Reedswamp and Hibiscus tiliaceus—Barringtonia racemosa Lagoon Fringe Forest, can be expected before the turn of the century. Dredging and mechanical control of vegetation will become necessary if major open water spaces are to be maintained.
Meiotic studies of some South African cultivars of <i>Lantana camara</i> (Verbenaceae)
Authors: Spies J. J. , Stirton C. H. 
Published: July 2015

Lantana camara L. is a polyploid species with a basic chromosome number of 11 (x = l l ) . Chromosome association in 39 cultivars indicated the occurrence of univalents to heptavalents with bivalents predominating. Multivalent association analysis revealed the presence in South Africa of at least four different groups of L. camara at the diploid level. The potential for sexual reproduction must exist, at least at the diploid level, to account for differences in chromosomal behaviour that can only be attributed to hybridization. The possibility exists that the basic chromosome number may be lower than 11, or else postspeciation genomic evolution must have occurred. No cytogenetical correlation exists between the South African and Indian cultivars. The number of chiasmata per genome increases with an increase in the polyploid level. Most multivalents are of the chain type. Univalents during diakinesis are the result of asynapsis. Triploid and pentaploid plants display a markedly abnormal meiosis. L. camara is a segmental allopolyploid species.
Embryo sac development in some South African cultivars of <i>Lantana camara</i>
Authors: Spies J. J. , Stirton C. H. 
Published: July 2015

Twenty embryo sacs from each of 20 different Lantana camara L. cultivars naturalized in South Africa were examined. The normal sexual embryo sacs were monosporic 8-nucleated embryo sacs of the polygonum type and were encountered in 55% of the material examined. Several deviations from this pattern were recorded. Occasionally one of the nuclei failed to develop into a synergid, resulting in three polar nuclei. Contrary to published information, the antipodal cells did not increase in size, nor was there an increase in the number of nuclei per cell. Although the occurrence of sexuality is confirmed, no definite evidence exists for the occurrence of apomixis. The occurrence of two embryo sacs per locule might be the result of either apospory or of sexuality whereby two embryo sacs were formed from two megaspores.
Southern African species of <i>Mentha</i> L. (Lamiaceae)
Authors: Codd L. E. 
Published: July 2015

The species of Mentha L. occurring in Southern Africa are reviewed and a key is provided to two indigenous and one naturalized species. M. wissii Launert is reduced to M. longifolia (L.) Huds. subsp. wissii (Launert) Codd.
A study of wood use for fuel and building in an area of Gazankulu
Authors: Liengme C. A. 
Published: July 2015

The utilization of wood for fuel and building timber was studied in a 13 000 ha area of Gazankulu, near Giyani. Headloads of firewood brought in by eight of the 978 families present were monitored during six periods in a year. The two most important sources of firewood are Colophospermum mopane and Combretum apiculatum. Firewood consumption is estimated at an average of 14,9 kg per family per day. The annual demand for firewood in the whole study area is, therefore, approximately 5 300 tonnes. Living-huts and storage-huts in the process of being built were examined. The mean volumes of wood in living-huts and typical storage-huts are 1,30 m3 and1,09 m3, respectively. 89 living- and 80 storage-huts were built in a year. The demand for finished timber in the study area in that year was approximately 231 tonnes. Timber use has not yet outstripped production, but it will do so soon if alternative timber sources are not provided.
Evolution des flores et de la végétation Tertiaires en Afrique, au nord de PEquateur
Authors: Boureau E. , Cheboldaeff-Salard M. , Koeniguer J. -C. , Louvet P. 
Published: July 2015

La repartition de la flore Tertiaire en Afrique, três différente de l’actuelle, se comprend si on tient compte de deux facteurs essentiels: la regression des mers épicontinentales vers le nord et la dérive du continent africain. II en résulte qu’á l'Eocêne inférieur, l’équateur se trouvait á environ 1 000 km au nord de sa position actuelle. Ces modifications aboutissent á des transformations importantes de l’environnement climatique et par consequent de la repartition des flores. Cela explique notamment la presence d’une mangrove en Libye avec Sonneratioxylon aubrevillei et en Egypte avec Nipa burtinii.La forêt dense est présente dans le Paléocêne du Tinrhert avec Entandrophragmoxylon normandii (comparable á l’actuel Entandrophragma angolense). Les formations de foret dense, développées á l’Eocêne, surtout sur le rivage, sont suivies plus au sud, d’une savane qui s’étend davantage á I’Oligocêne et qui peut atteindre la mer. Cependant, on trouve encore en bordure de mer á l’Oligocêne, des espêces de forêt dense comme Entandrophragmoxylon magnieri (comparable á Entandrophragma candollei) espêce qui avoisine des dépóts deltaiques avec de grands troncs qui indiquent une flore plus sêche (Detarioxylon aegyptiacum, Combretoxylon bussonii et Pterocarpoxylon tibestiense (rapproché du Pterocarpus erinaceus de savane), mais parfois accompagnée de troncs de forêt-galerie (Atherospermoxylon aegyptiacum, Monimiacée). Au Miocene, l’assechement continue et la savane progresse. Les Palmiers apparaissent et des galeries forestieres subsistent, mais même á proximité de la mer, le biotope est sec au Miocene inférieur dans le Nord de l’Afrique. Ce n’est que vers le sud que la végétation hygrophile apparait au niveau du Tibesti avec Myristicoxylon vincentii. Ainsi. prês de la position présente de l’Equateur, la mangrove se retrouve au Sénégal dans le Paléogêne du Cap-Vert avec des pollens de Rhizophoracées. Sonneratiacées, Avicennia et Nipa (Spinizonocolpites) et la forêt dense subsiste dans sa position actuelle entourée d’une savane.
Le bois petrifies de la plaine de la haute Rusizi (Burundi)
Authors: Reeksman M. 
Published: July 2015

THE DISCOVERY OF PETRIFIED FOSSILS IN THE HIGH RUSIZI PLAIN (BURUNDI)Palaeobotanical research in Central Africa is still very fragmentary. In Burundi, apart from the very classical and abundant stromatolites of the Mosso (in the south of the country), Sah (1967) has indicated the occurrence of vegetal debris in the fluviolacustrian sediments o f the mid-upper Rusizi plain. These fragments have never been identified, but a study of the pollen grains found in sedimentary layers of the same age has revealed some features of the vegetation and of the climate prevailing in the Upper Neogene period.In November 1978 we discovered in north-western Burundi a deposit of petrified trunks of exceptional size. These fossils had been exposed a short time previously when a small quarry was established. The deposit contained four trunks, two of which were large: length, 1 m; diameter, 90 cm; weight, more than 1 000 kg.Initial macro and submicrospic examination of fragments showed an anatomical structure similar to the structure of some fossils described in Kivu (Zaire) and belonging to the family Caesalpiniaceae.Samples were sent to Tervuren (R. Dechamps) and to Liêge (Mrs Demaret) and their joint studies revealed that these trunks belong to the genus Julbernardia and probably to J. globiflora. Their age would be about 1 200 000 years.Since then, other trunks have been found (at least ten). According to our study, it is concluded that they have a very different structure from those of the previous specimens. Samples were sent to Tervuren and to Liêge for further study and the conclusions from the specialists should be available very soon.
Interaction of ecology, taxonomy and distribution in some Mesembryanthemaceae
Authors: Hartmann H. E. K. 
Published: July 2015

Many taxa of the family Mesembryanthemaceae show close correlations between distribution and environmental factors, e.g. occurrence on limestone or quartzite only, but few cases have been studied in detail. Recent investigations in anatomy, morphology, life cycles, physiology, and in energetic properties indicate that fundamentally different patterns are developed in adaptation to arid conditions, even in reaction to identical edaphic and climatic factors.On the other hand, little is known about the immediate influence of changes in the natural environment. Studies in populations of the subgenus Cephalophyllum of the genus Cephalophyllum N.E. Br. show strong correlations between precipitation data and habit, which can superimpose genetic dispositions. In addition, growth forms are well adapted to certain types of plant communities, so that superficially, a diffuse structural pattern results.Long term studies, in the field and in the greenhouse, of growth forms in relation to time, to precipitation, and to associations, allow first suggestions for adaptive pathways in the evolution of the group, and the results form a basis for taxonomic decisions in this highly confused taxon. Finally, the example offers aspects for the better understanding of interaction between ecology and distribution data.