title: Extra petals in the buttercup (Ranunculus repens) provide a quick method to estimate the age of meadows.
abstract: OBJECTIVE
  There is a widely used crude method to estimate the age of hedgerows (Hooper's rule) based on species' richness. The aim of this study was to try and establish a similar field method for estimating the age of grasslands based on the accumulation of macro-somatic mutations.
  
  
  METHODS
  A countrywide survey was carried out by the British public to investigate the relationship between grassland age and the number of Ranunculus repens (creeping buttercup) plants with extra petals. In addition the relationship between grassland age and R. repens pollen viability was also investigated.
  
  
  RESULTS
  Each plant with flowers with additional petals in a sample of 100 was found to equate to approx. 7 years. A higher significant correlation was observed between pollen viability and population age; however, this is not amenable to providing field estimates.
  
  
  CONCLUSIONS
  The age of British grasslands can be easily and reliably estimated in the field by counting the number flowers with additional petals in R. repens in meadows up to 200 years old. An attempt to estimate the heritability of extra petals suggests that the phenotype results from the slow accumulation of somatic mutations in a species that primarily reproduces vegetatively.
authors.affiliation: Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Ceredigion SY23 3AL, UK. jhw@aber.ac.uk
authors.forename: John
authors.initials: J
authors.lastname: Warren
mesh_terms: D004463:Ecology / Q000379:methods*; D017753:Ecosystem; D035264:Flowers / Q000033:anatomy & histology*; D040582:Inheritance Patterns / Q000235:genetics; D011058:Pollen / Q000033:anatomy & histology; D031947:Ranunculus / Q000033:anatomy & histology*; D013997:Time Factors