Small four-tooth moss  (Tetrodontium repandum)

Information authenticated by Royal Botanic Gardens, Kew:
http://www.rbgkew.org.uk/

• Capsule: in mosses and liverworts, the spore-bearing structure, held aloft on a stalk called a seta. Capsules have a variety of shapes. Most moss capsules have a mouth, which is covered by a lid until the spores become ripe and the lid falls off, revealing a single or double ring of teeth, known as the ‘peristome’. The spores are released and dispersed in the wind. In liverworts the capsules do not have lids; when the spores are ripe the capsule splits into four, releasing the spores.
• 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.
• Spores: 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.
• 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.
• 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’.

1. Shaw, A. & Goffinet, B. (2000) Bryophyte Biology. Cambridge University Press, Cambridge.
2. Crosby, M. & Magill, R. (1978) A Dictionary of Mosses. Missouri Botanic Gardens.
3. Church, J. M., Hodgetts, N. G., Preston, C. D. & Stewart, N. F. (2001) British Red Data Books: mosses and liverworts. Joint Nature Conservancy Committee, Peterborough.
4. UK BAP (August 2002): http://www.ukbap.org.uk
5. Allaby, M. (1998) The Oxford Dictionary of Plant Sciences. Oxford University Press, Oxford.
6. Mosses and Liverworts in Wales (August 2002): http://home.clara.net/adhale/bryos/
7. Egerton, H. & Jones, F. (Eds.) (1998) Nature Encyclopedia. Dorling Kindersley, London.