This study shows that rhizomorphs can be produced readily in the laboratory for use in physiological and biochemical experimental. Apical and sub apical segments can be excised and treated experimentally like roots. The mean rate of phosphate uptake by apical segments as a function of phosphate concentration is very similar to that of rhizomorphs produced under more unnatural conditions. Phosphate uptake is bioasic with Km and Vmax ehemical analysis and NMR indicates that there is a sizeable amount of orthophosphate within the hyphae, located in tow pools-cytoplasmic and vacuolar with the bulk of the orthophosphate in the vacuole. Cytochemical, electrophoretic and NMR studies show that a significant proportion of the phosphorus is in the form of polyphosphate. It would seem that initially moist of the phosphate absorbed enters the vacuole as orthophosphate and there is little direct incorporation into polyphosphate.