Published online by Cambridge University Press: 28 March 2007
A regression equation was used to relate apothecium diameter to apothecium dry weight inXanthona parietina. This was used to estimate the contribution of apothecia to thallus weight in 80 randomly selected thalli from vertical concrete posts at Romney, Kent (mean 22–5%, range 0–87%). The energy contents of apothecia and the sterile thallus were found to be similar (17.6—18.2 KJ g−1 dry weight) and apothecium production was found to be independent of thallus aspect. The results are discussed with reference to apothecium growth rates and the allocation of resources in lichens.