Identification notes
This page concerns the current taxonomic concept of Leucobryum glaucum s.str., published following research by Tom Ottley and his co-authors in 2023 about the occurrence of Leucobryum species in Britain.
Fortunately, deep and extensive hummocks of Leucobryum glaucum plants of open moorland and heath are likely to remain as L. glaucum albeit in the new, more narrowly defined sense. However, beware smaller plants of Leucobryum in open habitats and others in shaded habitats – these could be either L. glaucum or L. albidum. A perennial difficulty with Leucobryum species is their inherent and often habitat-influenced variability so microscopic identification is advisable for plants of dubious identity.
Under the microscope, L. glaucum has 4-10 rows of shortly rectangular laminal cells with squared (not sloping) end walls and a sharply defined border 3 or more rows of narrowly elongate cells. In transverse section, the nerve usually differs from L. albidum in having a central V-shaped groove on the dorsal side (underside). Transverse pores are typically large – 10um or more wide.
