Isothecium interludens was previously known as Isothecium myosuroides var. brachythecioides and is mentioned in the Field Guide under that name.
Typical I. interludens is a robust, trailing plant, unlike the bushy, dendroid habit of I. myosuroides. It is more likely to be found in montane habitats than in lowland habitats (but beware, I. myosuroides can also be found in montane areas). The stem and branch leaves of I. interludens both have drawn out apices and are quite similar in shape. Typical I. myosuroides has more of a distinction between stem and branch leaves, with the branch leaves ending in a shorter point.Read the Field Guide account