Research was conducted to study the inheritance of the characteristic 'dentated leaves' in the autotetraploid grass species Dactylis glomerata. From segregation ratios of inbred and crossbred populations the following conclusions can be drawn: 1. Harshness of leaves is a dominant character. Simplex plants have a dominant phenotype but are less strongly dentated than duplex plants. 2. From the figures obtained it cannot be established with certainty how many genes are involved in the character harshness of leaves. Most cases can be explained by assuming one dominant factor, possibly supplemented by minor genes. However, the existence of complementary factors is not excluded, while also a system of more factors with partial dominance is a possible explanation. 3. The figures can be best explained by including the occurrence of double reduction in the computations. However, it is not possible to establish the coefficient a with reliability.