billbergia, any member of a genus (Billbergia) of evergreen epiphytes of the pineapple family (Bromeliaceae), containing more than 50 South American species. Several species are grown indoors as decorative plants for their colourful foliage, flowers, or bracts (leaflike clusters beneath the flowers). The stiff, spiny, often strap-shaped leaves grow in a rosette, sometimes up to 90 cm (35 inches) in diameter, directly from the root. The flowers are on a spike or panicle (loose cluster) growing from the centre of the rosette.