Calculations based on a recently derived theory for the non-saturating ion current of a flush mounted Langmuir probe in an oblique magnetic field are compared with the measured ionic branches of probe characteristics obtained in an electron cyclotron resonance (ECR) discharge. It turns out that the theoretical formula reproduces the shape of the measured curves well and also yields ionic densities in the outer region of the core plasma consistent with values obtained by other means in the same discharge under similar conditions.