What is "pitcairnioideae"

The Pitcairnioideae comprise the terrestrial subfamily of the bromeliads ( Bromeliaceae) with over 1000 species in 16 genera. Unlike the many epiphytes and lithophytes which make up the rest of the family, with a few exceptions, all of the members of this subfamily are either terrestrial or saxicolous. Common to arid and high-altitude regions, this subfamily is considered to have the most ancient lineage, more closely resembling its grassy relatives than the exotic novelties represented in the other two subfamilies. The commonly cultivated genera from this group include Dyckia, Hechtia, Pitcairnia, and Puya.