The Arabidopsis ZF-HD genes are all expressed in flowers, with some members being more ubiquitously expressed. Northern-blot analyses using various tissue types were carried out for all ZF-HD family members, with 13 shown; ATHB26 RNA could not be detected in any of the tested tissues. Twenty-five micrograms of total RNA was used for each tissue type: root, rosette (rosette leaves), cauline (cauline leaves), stem, inflorescence (stages 1–12), open flower (stage 13 on), and seedling.