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Common Foxglove Digitalis purpurea
The Extraordinary Peloric Foxglove
The name 'foxglove' in folklore is said to be because the fox uses the bell shaped flowers on his toes so he can silently stalk his prey. In 2015, an extraordinary foxglove flowered in my garden, entirely unsuitable for a foxes' toes. It had the usual bell shaped foxglove flowers along the spire, but at the apex was another large flower, more like a lily. Some research revealed that this was an unusual, but not unique, peloric foxglove. Other examples published online showed foxglove terminal flowers which were more like campanula flowers, not divided into individual petals. The terminal peloric flowers all have radial symmetry, with more petals and stamens than the flowers on the spike.
Terminal flower mutants have been recorded in several species of flowering plants, particularly of the mint family Lamiaceae, to which both foxgloves and snapdragons belong.
Peloric flower mutations seem relatively common in plants such as orchids and foxgloves and their relatives, because the abnormalities are much more obvious in groups with showy flowers. Many modern cultivars of Gloxinia have been bred to have only peloric flowers, which are larger and showier than the usual form.
A peloric flower of Digitalis purpurea (common foxglove)
Linnaeus, the C18th Swedish botanist, and father of modern taxonomy, found a mutant common toadflax, Linaria vulgaris, with radially symmetrical flowers. He first used the term 'peloria', after the Greek word for monster. In his mutant toadflax all the flowers were peloric, whereas in the foxglove only the terminal flower has this form. The peloric foxglove flower, sometimes called Digitalis purpurea monstrosa, has been described by botanists from the mid C19th onwards.
Charles Darwin investigated 'peloria' in snapdragons, while carrying out research on the inheritance of floral characteristics. Later it was found that in the common foxglove, Digitalis purpurea, the terminal flower mutation is inherited. It can be reproduced from seed via the peloric flowers or the normal flowers, which are all fertile. Unfortunately, I did not collect seed from the peloric foxglove in my garden.
The foxglove plant, which is poisonous, has been used in folk and modern medicine for centuries, in the treatment of heart disease. The eighteenth century physician, William Withering from Wellington in Shropshire, was the first to carry out scientific experiments with extracts from foxglove leaves, to treat heart disease. He is buried in Edgbaston Old Church, with a foxglove carved on his headstone.
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