Significance of different centres of diversity in subfamilies of poaceae in southern africa

Present-day distributions of grass subfamilies in southern Africa closely follow current climatic conditions. Of the five subfamilies, three predominate in easily-defined climatic regions that are correlated to photosynthetic pathways: Panicoideae (mainly C4 malate formers) in mesic summer rainfall regions; Chloridoideae (mainly C4 aspartate formers) in arid summer rainfall regions; and Arundinoideae (mainly C3) in regions with more than 40 % winter rainfall. The other two subfamilies have only C3 photosynthesis and are less wide-spread. Pooideae form a large component of the grass flora in high altitude areas of Lesotho, the eastern and southwestern Cape, and Bambusoideae has very few taxa and never forms a…