roothair defective primary root of germinating mutant kernel showing absence of root hairs. (Photos courtesy P. Schnable.)

roothair defective for comparison with rth1, primary root of germinating normal kernel showing normal root hairs. (Photos courtesy P. Schnable.)

roothair defective electron micrograph of the surface of an rth3 primary root showing aberrant "stocking cap" root hair initials. (Photos courtesy P. Schnable.)