Dynamic expression pattern of different clusters during flower development and GO function enrichment analysis. (a) Dynamic expression pattern of different clusters. Transcriptome profiling in pistillate flower buds of hickory shows highly coordinated expression during flower development. Nine major type patterns were identified, which were denoted as different color, respectively. The number of genes for each cluster represents in each panel. (b) Functional categorization of genes from different clusters. The color sets for each cluster are in strict accordance with part (a).