Cline of heavy-metal tolerance in Agrostis <>
    Most plants are unable to grow on heavy-metal contaminated soils ("tailings") on the margins of abandoned copper mines. Cu⁺⁺-tolerant forms of the grass Agrostis tenuis have been selected to grow on these soils [adult plants at 20~40m], but are poorly adapted to non-contaminated soil [adult plants at 0]. Wind-borne pollen is carried downwind , such that the seedling population at 60 ~ 100m downwind are more tolerant than the adult plants.

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Figure © Futuyma (1997) after Macnair (1981); Text material © 2005 by Steven M. Carr

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