High Plains Drifter, a Vagrant Moss Discovered in Northeast Oregon

I discovered balls of Grimmia ovalis Lind. growing in bunchgrass communities of the central Blue Mountains of northeastern Oregon in the spring of 2005. Although this species is found in many western states, the discovery of this unattached form appears to be new to North America. Hypotheses of moss ball creation are reviewed from existing literature and are evaluated as mechanisms in the creation of these particular moss balls.