The Australian heath plant, B. ornata (Proteaceae), has been grown in water culture at a low phosphate level (0�001 p.p.m. phosphorus). Such plants, 22 weeks or more in age, have been used for 24-hr uptake experiments with 3l1P-labelled orthophosphate. Characteristics of 32p distribution are a low translocation from roots to tops, and the formation of a large fraction of trichloroacetic acid-insoluble phosphorus in the roots.