Fig. 6.

Conceptual figure illustrating how different developmental trajectories in the bract scale/ovuliferous scale complexes of conifers may generate morphological diversity at pollination. Bars in the lower panel indicate the initiation and cessation of growth in the bract scales and ovuliferous scales in three hypothetical species of conifers. The plot in the upper panel depicts hypothetical curves comparing the size of bract scales to the ovuliferous scales at different points in their development (the exact shape of the curve would depend on growth rates in each structure). The specific morphology each species exhibits at pollination depends on when exactly pollination intersects these curves. Note that the greatest potential diversity in morphologies occurs relatively early in cone development, during the time period when species transition from bract-dominated to ovuliferous scale-dominated forms.