The subfamily Tillandsioideae of the Bromeliaceae comprise some 1500 species widespread in the neotropics, largely representing the entire range of the family. This group has undergone rapid speciation and adaptation to every niche, habitat and pollinator available. The plants occur as epiphytic or terrestrial, from sea-level beach dunes, desert sand dunes, epipetric on sheer rock faces, humid lowland rain forests, tropical dry forests, cloud forests, to high elevation páramos. Plants range from minute (6 cm long) epiphytes to enormous 3 m tall terrestrial tank bromeliads. Floral adaptation in corolla shape, color, and fragrance to its pollinators has taken place repeatedly. While most species are bright-colored, day-blooming, and hummingbird or insect pollinated, important species groups in such genera as Werauhia and Vriesea are specifically adapted to night-blooming and bat pollinators. Within this wide range of morphological variation, convergence and possible parallel evolution has contributed to the difficulty in circumscribing genera. The Tillandsioideae have been subject to various generic-level interpretations based largely on selective morphological characters primarily derived from studies of herbarium material. In particular, the genera Tillandsia, Vriesea, and Guzmania have long been recognized as artificially circumscribed. With the goal of achieving monophyletic and decisively natural genera, molecular studies into this fascinating group have been initiated. Combining the molecular data from plastid locus matK cpDNA sequences, and a different emphasis on some of the same morphological characters traditionally used in bromeliad systematics, new relationships in the subfamily are revealed that will result in a recircumscription of the genera.

Key words: Bromeliaceae, molecular systematics, taxonomy, Tillandsioideae