The hoop-petticoat daffodil is a dwarf daffodil that has become a common feature of British horticulture. Narcissus bulbocodium is found naturally in a wide range of open habitats in southwest Europe, including meadows, dunes, forest floors and rocky hill sides. Natural populations of Narcissus bulbocodium may be very large, the species can naturally propagate sexually via seed, and asexually by bulbs. Hoop-petticoat daffodils have been grown in Britain since the 1630s with the earliest garden escapes being recorded in the early 1900s. As the horticultural popularity of hoop-petticoat daffodils increased, populations have become naturalised, especially in rough grassland and waste places, across parts of southeast England.
There is considerable variation across the hoop-petticoat daffodil's native range, much of which has been brought into cultivation. The wild-type daffodil is yellow but colour mutants are known in cultivation. Furthermore, hoop-petticoat daffodil hybridises with other Narcissus species, increasing the range of variation available to gardeners. Other variation is less obvious, for example, the number of chromosomes found in the cells of individual plants ranges from 14 to 56, in multiples of seven.
Like all members of the genus Narcissus, the hoop-petticoat daffodil flower has a trumpet-like structure (corona) but unlike other Narcissus species, the corona is large relative to the surrounding 'petals' (tepals), giving the plant its common name. The corona is not unique to the genus Narcissus, it is found scattered across the evolutionary tree of the Amaryllidaceae, implying the corona probably arose more than once in the family.
Typically a flower has four concentric rings of structures, which, going from the outside to inside, are called: the sepals; the petals; the male anthers; and the female carpels. In many petaloid monocots, e.g., hyacinths, lilies and tulips, the sepals and petals are indistinguishable and are referred to as tepals. The Narcissus corona is found between the tepals and the anthers, which has raised the question of whether the corona is derived from petals, tepals or stamens.
For more than a century this question has been debated. Using anatomical and genetic tools, a group of researchers from the Department of Plant Sciences, Oxford, investigated the early developmental stages of the hoop-petticoat daffodil flower. These researchers suggest the corona is not a modification of the rings of floral structures found in the typical flower. Instead, the corona has a different origin; it forms from a region of tissue between the tepals and the stamens.
Waters MT et al. 2013 The corona of the daffodil Narcissus bulbocodium shares stamen-like identity and is distinct from the orthodox floral whorls. The Plant Journal 74: 615-625.