A prominent feature of plant genomes is their epigenetic landscape. The epigenome encompasses DNA methylation, histone modifications and other modifications not directly encoded in the genome. In general, DNA methylation is thought to mark permanent changes in the genome that must exist over the developmental lifetime of the plant, such as silencing transposable elements in embryonic tissue to protect the fidelity of the genome from transposition. Eichten et al. (2013, this issue) address the question of whether DNA methylation also specifies tissue types in maize. Using genome-wide array and sequencing technologies to assess DNA methylation and gene expression in two maize inbreds, B73 and Mo17, across four tissue types (leaf, immature tassel, embryo and endosperm), the authors find that there are more differentially methylated regions (DMRs) between maize inbreds than in the tissues they sampled (Eichten et al., 2013). The DMRs that were identified between tissue types did not correlate with subsequent expression changes suggesting the DMRs were not in fact functional in specifying tissue type. Despite other plants such as tomato that display tissue and developmentally regulated DMRs (Zhong et al., 2013), this may not be a general phenomenon in other species such as maize, which highlights the need to functionally define genomic elements in specific species.