Figure 1.

Network approach to characterizing interactions among reproductive parts. (a) Cross-section and external view of hypothetical reproductive structure with part types numbered from zero (the sporangium). (b) Networks (left) and adjacency matrices (right) based on (a), with part types depicted as numbered nodes and the five types of interactions among them as undirected, unweighted edges. Nodes interacting with themselves indicated by self-loops. Adjacency matrices represent the number of edges connecting pairs of nodes in the networks. For each reproductive structure, we scored a ‘complete’ network depicting all interactions among nodes and a ‘backbone’ network with only attachment interactions; red numbers indicate distance of the nodes in attachment edges from the sporangium. (c) Plot of degree (total edges incident to a node) in complete network from (a, b) as a function of shortest backbone distance from the sporangium.