Slender thread-moss (Orthodontium gracile)

Slender thread-moss
Loading more images and videos...

Slender thread-moss fact file

Slender thread-moss description


Slender thread-moss grows in bright green cushions, and closely resembles a much commoner species Orthodontium lineare. It requires an expert to tell them apart, but slender thread-moss has slightly narrower leaves. Mosses are difficult plants to identify, needing knowledge and a scientific field guide to be sure of which species you are looking at.

Length: up to 10 mm

Slender thread-moss biology

Mosses are plants, but they belong to the lower orders. They do not produce flowers or seeds, but reproduce by spores or vegetatively. Neither do mosses have a vascular system for conveying sap, nor do they have roots to absorb water. Mosses have rhizoids, which fulfil the role of a root system in anchoring the plant to a surface. Water and nutrients are absorbed over the entire surface of the plant.


Slender thread-moss range

This moss has a wide world range, being found in western France, North and South America, and tropical Africa. In the UK since 1970, it has been recorded in East Sussex, Cheshire, mid-West Yorkshire and Midlothian.

You can view distribution information for this species at the National Biodiversity Network Atlas.

Slender thread-moss habitat

In the UK, slender thread-moss grows on damp, shaded, vertical, acid rock surfaces, and sometimes in crevices. In France, it is found on sandy soil at the base of trees, and occasionally, on rotting wood. It has very occasionally been recorded on rotting wood in England.


Slender thread-moss status

Classified as Vulnerable in the UK. Classified as Endangered in Europe.


Slender thread-moss threats

Never a common species, slender thread-moss may possibly have declined through the introduction of the similar O. lineare. Other factors may be due to changes in the microclimate or acidic water pollution.


Slender thread-moss conservation

Slender thread-moss is listed in the UK Biodiversity Action Plans (UKBAPs), and included in English Nature's Species Recovery Programme (SRP). This moss's existence may be precarious, and all the sites where it is known to occur are protected. It is also being grown ex-situ as an insurance against its loss in the wild, and trials are underway to re-introduce the species to suitable sites. As it may be threatened by an introduced species, it might be possible, under supervision, to clear competing mosses to allow slender thread-moss to re-colonise the sites. In the meantime, bryologists are being asked to pass on any records they have of this moss, to enable greater knowledge of its ecology and its true status to be gathered.

There may be further information about this species available via the National Biodiversity Network Atlas.
The UK Biodiversity Action Plan for this species is available at UK BAP.


This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:


Measures to conserve a species or habitat that occur outside of the natural range of the species. E.g. in zoos or botanical gardens.
Thread-like structures that help to anchor the plant to the substrate, and absorb minerals and water. In liverworts they consist of a single cell, in mosses they are multi-cellular.
Microscopic particles involved in both dispersal and reproduction. They comprise a single or group of unspecialised cells and do not contain an embryo, as do seeds.
Vascular system
In plants, the system that allows water and nutrients to move around.
Vegetative reproduction
Type of asexual reproduction (reproduction without recombination of genetic material) that results in the propagation of plants using only the vegetative tissues such as leaves or stems. The resulting plant is genetically identical to the original plant. A well-known example of this is the reproduction of strawberry plants from 'runners'.



Image credit

Slender thread-moss  
Slender thread-moss

© British Bryological Society / National Museum & Gallery, Cardiff

National Museum & Gallery, Cardiff
Cathays Park
CF10 3NP
United Kingdom


Link to this photo

Arkive species - Slender thread-moss (Orthodontium gracile) Embed this Arkive thumbnail link ("portlet") by copying and pasting the code below.

Terms of Use - The displayed portlet may be used as a link from your website to Arkive's online content for private, scientific, conservation or educational purposes only. It may NOT be used within Apps.

Read more about



MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite Arkive images and videos and share them with friends.

Play the Team WILD game:

Team WILD, an elite squadron of science superheroes, needs your help! Your mission: protect and conserve the planet’s species and habitats from destruction.

Conservation in Action

Which species are on the road to recovery? Find out now »

This species is featured in:

Help us share the wonders of the natural world. Donate today!


Back To Top