Stabler's rustwort (Marsupella stableri)
|Size||Length: up to 15 mm (2)|
Classified as Nationally Scarce in Great Britain (3).
This small, leafy liverwort grows in pinkish-green to rosy red, or occasionally purplish-brown or coppery coloured mats (4) (2). It has often been confused with the related species Marsupella boekii (3). Detailed examination can distinguish the two, with the leaves of Marsupella boekii usually being spaced further apart, and less closely pressed to the stem. Marsupella boekii also often lacks the rosy colour seen in Stabler's rustwort (2).
This liverwort has been recorded from sites in Scotland, the Lake District and from two sites in north Wales (3). The range outside of Britain is unclear, due to confusion with Marsupella boekii, but Stabler's rustwort has been recorded from western Norway and Canada (3).
Found in mountains at altitudes of between 300 and 1160 m, where it grows on wet or moist, steeply sloping to vertical acidic or mildly basic rocks, including rocks and gravely soil (3) (2). Typical habitats supporting this species are flushed with water periodically throughout the year (3).
Liverworts, hornworts and mosses form a group of plants called bryophytes (5). Bryophytes lack many of the more complex structures of the higher plants, such as a vascular system, and flowers. They do not have roots, instead they have structures called 'rhizoids' which absorb water and anchor the plant to the substrate. In liverworts these rhizoids each consist of a single elongated cell (6). Bryophytes have an interesting life cycle, which consists of two main stages, called the gametophyte and sporophyte generations, the gametophyte generation is dominant (6).
The threats facing this species are not understood, but it seems likely that the building of ski lifts and disturbance and erosion caused by walkers and climbers may have resulted in losses of Stabler's rustwort in some areas (3).
This liverwort is a UK Biodiversity Action Plan (UK BAP) priority species; a Species Action Plan has therefore been produced to guide its conservation (3). The plan aims to maintain viable populations throughout the current range of the species. A large number of the present sites that support this species are designated Sites of Special Scientific Interest (SSSIs), and some occur in National Nature Reserves (NNRs), the species therefore benefits from a degree of protection at these sites (3).
Information authenticated by Royal Botanic Gardens, Kew:
- Gametophyte: a life cycle stage in plants, which has one set of chromosomes (threads of DNA protein) in the cell nucleus (a condition known as ‘haploid’), which arises from a spore (which is also haploid). Sex cells (gametes) are produced during the gametophyte stage. This is the dominant life-cycle stage in liverworts and mosses.
- Rhizoids: 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.
- Sporophyte: the stage of a plant life cycle that produces spores (microscopic particles used in dispersal and reproduction). This stage is diploid (in the cell nucleus there are two sets of chromosomes - threads of DNA protein) and is dominant in ‘higher’ plants such as flowering plants.
- Vascular system: in plants, the system that allows water and nutrients to move around.
- National Biodiversity Network Species Dictionary (September 2002) http://www.nhm.ac.uk/nbn/
- Paton, J. A. (1999) The liverwort flora of British Isles. Harley Books, Colchester, UK.
- UK BAP Species Action Plan (September 2002): http://www.ukbap.org.uk
- Hill, M.O., Preston, C. D. & Smith, A. J. E. (1992) Atlas of the bryophytes of Britain and Ireland. Volume 1: liverworts. Harley Books, London.
- Church, J. M., Hodgetts, N. G., Preston, C. D. and Stewart, N. F. (2001) British Red Data Books: mosses and liverworts. Joint Nature Conservation Committee, Peterborough.
- Mosses and Liverworts in Wales (May 2002): http://home.clara.net/adhale/bryos/