Fig. 4. Among‐family variance for the response variables proportion of plants flowering, weeks to initiation of flowering, and seed yield per plant in each of four B. tectorum populations in response to vernalization as seeds or as plants. For each response variable, bars headed by the same letter are not significantly different at the P < 0·05 level according to Levy’s multiple comparison test for differences among variances. PP, Potosi Pass; WR, Whiterocks; HC, Hobble Creek; ST, Strawberry.