Over 24 000 plant taxa are known to occur in the southern African flora, which is extraordinarily rich on a species/area basis. Lists of species and infraspecific taxa recorded for the six major biomes, Fynbos, Savanna,Grassland, Nama-Karoo, Succulent Karoo and Desert, were obtained from the PRECIS specimen database.These lists were analysed by numbers of unique and shared species and infraspecific taxa. by differential occurrence and life forms of large genera, and by differential occurrence of families. Each biome is floristically distinct except Nama-Karoo. The biomes form two main groupings, those with winter rainfall and those with summer rainfall. Succulent Karoo is most similar to Fynbos and Nama-Karoo is most similar to Savanna.
The intensity of plant collecting in southern Africa is mapped using records from the Pretoria National Herbarium Computerized Information System (PRECIS), For the entire area, over 85% o f the quarter degree grid squares have fewer than 100 specimens recorded. Collecting intensities are compared for different countries, biomes and climatic zones. Future field work from the National Herbarium will be concentrated in areas most seriously under-collected.
Alloteropsis semialata (R. Br.) Hitchc. sensu Chippindall (1955) and Clayton (in press) is the only known grass species in which elements with both non-Kranz and Kranz leaf blade anatomy, and therefore with C3 and C4 photosynthetic pathways are included. In the past, two taxa had been recognized, but the characters used to separate them were found to be unreliable, so they were united. However, study of voucher specimens for anatomical and physiological work has shown that C3 and C4 taxa may be separated on the basis of morphological characters that differ from those considered in the past. Therefore, two taxa are again recognized, this time at the rank of subspecies, and the name Alloteropsis semialata subsp. eckloniana (Nees) Gibbs Russell stat. nov. is published.
The southern African flora has been surveyed for the first time at species level in the List of Species of Southern African Plants (Gibbs Russell e tal., 1984). The numbers of taxa recorded for southern Africa are compared to the numbers reported from other parts of Africa, and the largest families in each area are listed and compared The species richness of southern Africa is compared to that of other parts of the world. The numbers of genera, species and infraspecific taxa are given for each familv in the souihern African flora, and compared to previous counts bv Dyer (1975. 1976) and Goldblatt (I97H).
Ehrharta Thunb. is a genus o f Gondwanaland distribution with its centre o f diversity in the winter rainfall Fynbos Biome o f southern Africa. In recent subfamily treatments Ehrharta has proved difficult to place satisfactorily, and during the past five years it has been moved between Bambusoideae and Arundinoideae. However, most previous systematic studies using cryptic characters have covered only four taxa out o f about 35. The present study includes all African taxa, and demarcates seven species groups on the basis of both spikelet morphology and leaf blade anatomy. Parallelism and/or convergence in vegetative macromorphology within and between the species groups is widespread, and is similar, in some cases, to adaptations found in other plant families in the Fynbos Biome. However, these macromorphological trends are not reflected in the leaf anatomy. Leaf anatomy is generally consistent with the spikelet morphology. Some anatomical differences between the species groups in Ehrharta appear to be as great as differences between taxa of much higher ranks elsewhere in the Poaceae. This wide range of variability may be related to an early divergence o f Ehrharteae from other grasses, as suggested by the Gondwanaland distribution, and may explain the difficulty of placing this fascinating yet baffling genus in a subfamily. UITTREKSELEhrharta is 'n genus van Gondwanaland-verspreiding met sy middelpunt van verskeidenheid in die winterreenval-Fynbosbioom van suidelike Afrika. In onlangse subfamilie-behandelings is dit moeilik gevind om Ehrharta bevredigend te plaas, en gedurende die afgelope vyf jaar is dit oor en weer in Bambusoideae en Arundinoideae geplaas. Die meeste vorige sistematiese ondersoeke waarin verskuilde kenmerke gebruik is, het slegs vier taksons uit ongeveer 35 gedek. Die onderhawige ondersoek sluit al die Afrika-taksons in, en baken sewe spesiegroepe af op grond van die morfologie van die blompakkie en die anatomie van die blaarskyf. Parallelisme en/of konvergensie in vegetatiewe makromorfologie binne en tussen spesiegroepe is wydverspreid en is in sommige gevalle soortgelyk aan aanpassings wat by ander plantfamilies in die Fynbosbioom aangetref word. Hierdie makromorfologiese neigings word nie in die blaaranatomie weerspieel nie. Blaaranatomie is oor die algemeen in ooreenstemming met die morfologie van die blompakkie. Sommige anatomiese verskille tussen die spesiegroepe in Ehrharta blyk net so groot te w ees soos verskille tussen taksons van 'n veel hoer rang elders in die Poaceae. Hierdie wye verskeidenheid mag verband hou met 'n vroee divergensie van Ehrharteae vanaf ander grasse, soos aangedui deur die Gondwanaland-verspreiding, en mag 'n verklaring bied waarom hierdie bekorende maar raaiselagtige
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