to be a valid species (i.e. in the Flora Europaea (1976), and the Euro+Med Plantbase (2011)), as well as classified as D. purpurea subsp. dubia in 1922, or Digitalis purpurea f. dubia by Spanish taxonomists in 1983. Ecology Digitalis purpurea grows in acidic soils, in partial sunlight to deep shade, in a range of habitats, including open woods, woodland clearings, moorland and heath margins, sea-cliffs, rocky mountain slopes and hedge banks. It is commonly found on sites where the ground has been disturbed, such as recently cleared woodland, or where the vegetation has been burnt. Larvae of the foxglove pug (Eupithecia pulchellata), a moth, consume the flowers of the common foxglove for food. The caterpillars of this moth crawl into the newly opening flowers, one caterpillar to a flower. It then spins a silken web over the mouth of the flower, sealing it, and then proceeds to feed on the stamens and developing seeds. When the other uninfected flowers fall off, the corolla of the infected flowers remain on the plant, and the caterpillar then pupates in the flower. The species is uncommon, it has been recorded in Britain, Germany, Switzerland and Austria. Other species of Lepidoptera have been recorded eating the leaves, including Mellicta athalia and Xestia ashworthii in Britain, Eurodryas aurinia in Romania, and Mellicta deione in Portugal. Genetics The colours of the petals of the Digitalis purpurea are known to be determined by at least three genes that interact with each other. The M gene determines the production of a purple pigment, a type of anthocyanin. The m gene does not produce this pigment. The D gene is an enhancer of the M gene, and leads it to produce a large amount of the pigment. The d gene does not enhance the M gene, and only a small amount of pigment is produced. Lastly, the W gene causes the pigment be deposited only in some spots, while the w gene allows the pigment to be spread all over the flower. This combination leads to four phenotypes: M/_; W/_; _/_ = a white flower with purple spots; m/m; _/_; _/_ = an albino flower with yellow spots; M/_; w/w; d/d = a light purple flower; M/_; w/w; D/_ = a dark purple flower. Cultivation The plant is a popular ornamental, providing height and colour in late spring and early summer. Cultivated forms often show flowers completely surrounding the