Convolvulus arvensis stem explants form callus when inoculated on to 0.5 mgm/1 2, 4-D, 15 per cent coconut milk, and on to 1 mgm/1 kinetin, 15 per cent coconut milk. In the latter case numerous shoots are formed on the callus. Callus formed on explants on 0.05 mgm/1 2, 4-D, 15 per cent coconut milk formed shoots with in-creasing vigour when transferred to a medium (1) in which the 2, 4–D concentration is lowered by one-tenth, (2) which contains no auxin but kinetin at 1 mgm/1, (3) which contains kinetin at 1 mgm/1 and 15 per cent coconut milk. On NAA/ kinetin media shoots may form in which the intenode development is suppressed, giving compressed shoots. The capacity of callus to form shoots may be retained or lost through repeated sub-culture. Roots are formed erratically. The results are discussed, particularly with regard to the loss of morphogenetic potential and whether this is reversible.