Identification notes

This page covers the plant now recognised as T. herzogii which, with T. brachydontium s.str. and T. littorale, was segregated from T. brachydontium Bruch in Britain and Ireland in 2024.Until the second edition of the BBS Field Guide is published, the current FG species page refers to T. brachydontium agg.

T. herzogii is thought to be the scarcest and most habitat-restricted of the three, but is quite distinctive (at least under the microscope!). Its reddish shoots have narrow, strongly channelled leaves with longly acuminate to subulate tips. They are not fragile or twisted, nor do they have well-developed marginal teeth. Under a microscope, the cells in the basal part of the leaf are the same colour as those higher up and they are often thick-walled. Care needs to be taken in the field not to confuse this species with others that grow in quite deep cushions, including T. crispulum and Bryoerythrophyllum recurvirostrum.

For further details, and a key to Trichostomum, see the Resources section of this page.

Distribution in Great Britain and Ireland

The distribution map in the 2014 Atlas is for T. brachydontium agg., so includes all three segregates. As yet, a clear picture of distribution of each of the segregate species has not emerged, apart from T. herzogii, which is more or less restricted to limestone and other hard calcareous substrates on sheltered crags and gorges. A preliminary distribution map of each of the three segregates is included in the 2024 Field Bryology article.