The extent of endomycorrhizal colonization of Dasiphora floribunda was measured in 8 calcareous wetlands in eastern New York State, USA. Environmental parameters (pH, conductivity, water-table depth, soil moisture, soil organic matter, soil NH₄ , soil available P, and porewater DIP) varied among wetlands. Soil available P was relatively low and ranged from 2.52 to 15.74 mg-P gdw⁻¹ in all 8 wetlands. Contrary to expectation, the extent of endomycorrhizal colonization of D. floribunda did not vary among calcareous wetlands of different soil phosphorus or moisture status. Mycorrhizal colonization of D. floribunda ranged from 66.7 to 91.7%, with an average of 78.1 ± 7.7%. Although environmental parameters were only measured once, these results suggest that soil available P and soil moisture, used to predict variation of endomycorrhizal colonization of other wetland plants, are not useful for predicting the extent of endomycorrhizal colonization of D. floribunda. We propose that calcareous wetlands in eastern New York are an endpoint on a continuum of wetland types where P availability is so low that variation of P status among calcareous wetlands is not ecologically significant in the regulation of endomycorrhizal colonization.