The serpentine Knautia arvensis populations showed significantly lower mycorrhizal colonisation than their non-serpentine counterparts. The mycorrhizal colonisation positively correlated with soil pH, Ca and K concentrations and Ca/Mg ratio.
Serpentine populations of K. arvensis did not show higher mycorrhizal growth dependence than non-serpentine populations when grown in their native soils and inoculated with native AM fungi.