A review is given of the literature and original work by the authors on the detailed biology of 2 abundant and widespread weeds of the British Isles. The material is presented under the headings: description of the spp. (including vars.); geographical and altitudinal distribution; habitat; communities; response to biotic factors (including chemical and cultural control measures); gregariousness; performance in various natural and controlled environments; morphology; means of reproduction; chromosome number; physiological data; effect of frost, drought, etc,; phenology; floral biology; hybrids (including a full description of the common hybrid Rumex crispus x R. obtusifolius); seed production, dispersal, viability and germination; seedling morphology; effective reproduction; animal and plant parasites; history; and economic importance. In many sections the maritime and inland varieties of R. crispus are contrasted.