Experiments were performed to study sources of variation between ramets of a clone, and differences in growth form between plants from two locally specialized populations of Ranunculus repens in a woodland and a grassland site. In one experiment, ramets were taken from different positions along each of five primary branches of clones. For both populations variability in growth parameters of ramets of each clone was attributed to the position of a ramet within a branch, and not to any differences between branches of a clone.
In clones which are made up of several interconnected ramets, these ramets may: (1) compete with each other for light and other resources; and (2) supply each other with resources. In clones where connections have been lost only (1) above, will pertain. In a second experiment clonal material selected from the two populations was grown in flats under conditions of high ramet densities. For each clone, in half of the replicates, stolon connections between ramets were severed; in the other half stolons were left intact. In clones originating from the grassland population, ramets of the same genotype accumulated significantly more total dry wt and had more above-ground biomass when they were interconnected than if stolons had been cut. In clones from the woodland population, total dry wt was not significantly altered. In plants from both populations, after connections were cut, the distribution of dry matter to various plant organs was significantly altered (plants distributed more dry matter to inflorescences and ramet caudices, and less to stolons). The pattern of proportionate allocation of dry matter suggested that below-ground competition was more intense when stolons had been severed.
Growth form and the response to intraclonal competition are discussed in terms of local specialization in the woodland and grassland sites.