Geographical differences in leaf resin components of Eremophila fraseri F. Muell. (Myoporaceae)

Eremophila fraseri occurs in arid and semiarid areas of inland and northern Western Australia. The spreading bushes, 1 to 2.5 tn high, are covered with a thick, viscid layer of resin. The flavonoid and terpenoid components of the leaf resins were identified by thin-layer chromatography. Five types of resin patterns were recognized, and each was found to have a distinct geographical distribution. Each occurs sympatrically with at least one other resin pattern. It is suggested that hybridization between two tetraploid races is occurring, and that the progeny can be recognized by their resin com- position.