This is the rarest of our Hedwigia species and, although it was first recognised as long ago as 1829, it has subsequently been overlooked. It grows on boulders and acid rocks in upland areas and when dry it bears a strong resemblance to H. ciliata var. ciliata. In this state, its furrowed leaves may be visible with a hand-lens, but in some plants this character is poorly developed. When plants have capsules, as they often do, it’s worth examining the inner perichaetial leaves to make a confident identification.
An article in Field Bryology, which describes the characters of H. striata, can be downloaded at the bottom of this page.