Bulbophyllum has approximately 1500 species distributed throughout the Old and New World tropics. Many segregate genera have been established, and Bulbophyllum itself has been subdivided into 6-8 subgenera and numerous sections. Some sections are poorly circumscribed and many morphological characters cannot be unambiguously partitioned into discrete states. We have used nucleotide data in an attempt to clarify relationships in Bulbophyllum. The internal transcribed spacer (ITS) region of nuclear ribosomal DNA was chosen because initial data indicate sequence divergence levels in this region range from 2%-12%. Preliminary results indicate that some of the segregate genera proposed are not supported by molecular data although some sections may be supported.

Key words: Bulbophyllum,ITS,molecular systematics,Orchidaceae