This is the initial CRAN release of an R package implementing Bayesian inference for differential equation models. A preprint describing this method is available at https://arxiv.org/abs/1605.00021 The package is derived from methods and code published in Voyles et al. (2012)(http://dx.doi.org/10.1002%2Fece3.334) and Johnson et al. (2013)(http://doi.org/10.1890/12-0650.1). Software development is supported by NSF grant PLR-1341649. This release reflects the state of the package at the time of the initial submission of the companion paper to arXiv.org.