Thallus: type of simple plant body that does not have stems, leaves and roots.
References
Church, J.M., Coppins, B.J., Gilbert, O.L., James, P.W. & Stewart, N.F. (1996). Red Data Book of Britain and Ireland: lichens. Volume 1: Britain. The Joint Nature Conservation Committee, Peterborough.
Purvis, O. W., Coppins, B. J., James, P. W. & Moore, D. M. (1992). The lichen flora of Great Britain and Ireland. Natural History Museum Publications. The British Lichen society, London.