Marsh Clubmoss
Lycopodiella inundata
A rare wetland plant, associated with heathland and peat pools.
- Marsh Clubmoss (Lycopodiella inundata). Copyright Ian Ralphs
Description/identification
Marsh Clubmoss Lycopodiella inundata is not a true moss but a primitive non-flowering plant which is more closely related to ferns.
It has a distinctive lime-green colour and looks like the young tips on the ends of spruce trees. It has creeping horizontal stems that grow to between 5-20cm in length and vertical spore producing shoots, 5-8cm tall, which appear in late summer. Plants will grow and divide, and it is common to find v-shaped plants in the process of sub-division, or divided plants with only half of the v developed. The strobili form at the junction of the v and may be up to 10cm high.
Habitat
Marsh Clubmoss is associated with wet heathlands and peat pools, growing alongside other acid loving wetland plants such as White Beak-sedge Rhynchospora alba, sundews Drosera spp. and Sphagnum mosses. It grows on the margins of small pools, which may form in depressions in trackways or sloping seepage mires – but always where there is some disturbance, e.g. grazing, movement of machinery or small scale turf cutting to maintain very open conditions and a ready supply of bare ground. It has also been recorded on the margins of oligotrophic lakes and in abandoned quarries, but always where there is deposition of silt and fluctuating water levels to maintain open conditions.
Water levels must remain just below the surface of the soil in the summer months. Marsh Clubmoss cannot withstand permanent inundation but equally it cannot survive where the soil dries out completely. White Beak-sedge (pic from species dossier) is so typical of this bare wet peat habitat that it provides a good indication of suitable habitat for Marsh Clubmoss. Groundwater fed pools with fluctuating water levels are ideal, as the habitat remains free from dominant stands of either heathland or mire vegetation. Shallow peat cuts and the transitional zone on valley slopes often provides the ideal balance between wet and dry.
Life Cycle
After 2 years, fragments clone by the disintegration of the older section, slowly spreading at 2 to 10 cm per year. Spores distribute by air or water. Dies back to terminal buds in the winter.
Marsh clubmoss is a pteridophyte (a group including the ferns, horsetails and other clubmosses). It is a non-sexual sporophyte and disperses by producing small cloned fragments by the disintegration of the older section. Although it theoretically it can reproduce through a gametophyte stage, this has never been directly observed in British populations. Therefore it seems likely that much of the local propagations is through vegetative growth and division of individual shoots.
Distribution and threats
The grazed wet heathland habitats favoured by Marsh Clubmoss have undergone a massive decline throughout its north-west European range and as a result the UK now holds a substantial proportion of the global population. Historically, the species occurred in about 250 ten km squares but is now restricted to just ten scattered areas. It is classified as Endangered in the Red Data list for Great Britain, and protected under Schedule 8 of the Wildlife and Countryside Act and as a Section 41/42 Priority Species.