The effect of branching angle on adaptive growth in patchy environments

In clonal plants, the genetic individual (genet) develops via the production of multiple physiological individuals (ramets). The branching angle between the ramets can significantly influence the shape of the developing clone. We investigated the adaptive significance of this phenomenon by means of a spatially explicit dynamic model of clonal growth. We studied the effect of the branching angle on the efficiency of filling habitat patches, varying the sizes and shapes of the patches. Two growth forms were compared: the Narrow Range (NR) versus Wide Range (WR) form. In the NR plant, the branching angle was always acute, while in the WR plant, both acute and wide angles could occur. We hypothesized that the NR plant would be less successful, as narrower branching constrained the plant’s ability to turn. The simulations revealed an opposite trend: the NR plant occupied more space in most of the simulated habitats. However, the effect was weak in general. We conclude that the branching angle between ramets is likely to be a neutral trait in terms of natural selection.