The chemistry of the floral oils of Phymatidium delicatulum and P. tillandsioides (Orchidaceae) is described. These small epiphytes produce the oils in a complex gland (the elaiophore) located on the median petal. The floral oils of P. tillandsioides were shown to be comprised mostly of acylglycerols, as in many other Oncidiinae orchids from southeastern Brazil. Surprisingly, the floral oil of P. delicatulum was composed, predominantly, of relatively simple linear hydrocarbons. Evidence that P. delicatulum is pollinated by females of the oil-gathering bee genus Tetrapedia (Apidae: Tetrapediini) is presented.19757761