Slender Mouse-tail Moss - Isothecium myosuroides


Isothecium myosuroides has a distinctly tree-like growth form, its main stems growing away from the substrate, unbranched in the lower part, and bushily branched above. It often occurs in pure, dense mats, so its tree-like form may not be immediately apparent. It often grows on inclined or vertical surfaces, with the stems and branches curving downwards. Shoots are typically 1 to 2 cm tall. Stem leaves, especially towards the base of the stem, are about 2 mm long, broadly egg-shaped to triangular with a heart-shaped base, rapidly contracting to a finely tapering tip. Branch leaves are 1 to 1.5 mm long, narrower, triangularly spearhead-shaped, and taper to a shorter but still slender, rather sharply toothed tip. The single nerve ceases above mid-leaf. Capsules are 2 to 2.5 mm long, frequent in some regions, elliptical, slightly asymmetrical and inclined. The lid has a long beak.

Identification difficulty

It grows on boulders and tree trunks in woodland and shaded places, but may occur in the open. It does not grow on strongly base-rich rocks such as limestone. It is abundant in rocky, upland woods on siliceous and non-calcareous substrates, and in western areas may dominate trunks of oak and other trees.

When to see it

All year round.

UK Status

Widespread and fairly frequent in Britain.

VC55 Status

Fairly frequent in Leicestershire and Rutland.

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Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map