FIGURE 3. Distribution of Pteridium taxa in eastern South America. Black circles: P. arachnoideum subsp. arachnoideum s. str., white triangles: P. arachnoideum subsp. campestre, A. Scheme of the Dry Diagonal (shaded area, by R. Pinto) in South America. B. Detailed distribution of Pteridium taxa in north-eastern Brazil, elevation in gray scale (from white to black) for each 500 m.