In many areas this is a less common moss than I. myosuroides. Although it can often be be found in the same kind of tree-base habitat, I. alopecuroides is considerably larger and sometimes looks more like a form of Thamnobryum alopecurum than another Isothecium.
As with all four of our Isothecium species, there is an easy way to check you have the correct genus. If you’re deft enough, carefully pull off a few stem leaves to expose others left in situ. Examine the basal angles of the leaves with a good hand-lens and you will see dark patches, which are opaque alar cells. Thamnobryum does not have these and in any case has much shorter leaf cells.
When you realise it’s an Isothecium, you’ll notice that the plants have the shrub-like sub-dendroid branching form of its two smaller cousins. Unlike I. myosuroides and I. holtii, which are calcifugous, I. alopecuroides often prefers moderately basic habitats.Read the Field Guide account