summary For a number of species, population biologists have estimated the age of apparent clones. In studying a colony of naturalized Aster novi-belgii L. (first recorded as Aster salignus Willd.) growing at Wicken Fen Nature Reserve, Cambridgeshire, England, we have attempted to determine from a considerable body of historic records, its age, structure and development. While it is highly likely that the records refer to the colony in its present position on the Fen, there is uncertainty about its age and conflicting information about its position. A. novi-belgii is a self-incompatible species. Plants of the Wicken colony exhibit little variation and preliminary tests show that their achenes are sterile. As a working hypothesis, for further testing, we suggest that all the plants may be of a single clone. Population biologists, who are interested in determining the age and development of clones of plants, are likely to be disappointed both by the extent and the vagueness of historic records. This situation is understandable as the information was recorded for taxonomic purposes. The hope is expressed that the intensive studies now being made of populations of plants will result in the long-term survival in the public domain of detailed records and maps, which will enable future generations to study the age and development of clones of herbaceous species. [ABSTRACT FROM AUTHOR]