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(1) The demographic behaviour of two Viola species (V. fimbriatula and V. lanceolata) from open clearings is reported and compared with that of three woodland species. (2) Measurements were made of the size of the seedbank in the soil, germination, number and growth of seedlings numbers of pre-reproductive and reproductive ramets, and fecundity over five years. Seedling growth seed weight and number leaf production and grazing losses and investment in reproductive structures were also studied. (3) Seed banks of the clearing species were larger by a factor of five than those of the forest species. All showed plasticity in many characteristics but the clearing species produced more seeds per plant and lighter seeds. Clearing species grew faster than forest species. Irrespective of habitat, rhizomatous species produced more seed than stoloniferous species. (4) Conclusions are drawn from the entire series of papers Viola populations appear to be demographically unstable. [ABSTRACT FROM AUTHOR]

Studies the population biology of the Genus viola. Mechanism of adaptation of three species of violet, Viola sororia, V. blanda and V. pallens; Size of the soil seed bank of V. blanda and V. pallens; Calculation of the violets' population flux, age distribution, survival, and life expectancy.