Specimens of "Acacia pycnantha" were planted near the entry. Like other wattles, "Acacia pycnantha" fixes nitrogen from the atmosphere. To mark Australia Day in 1990, a 41c stamp labelled "Acacia pycnantha" was issued. Australia's floral emblem was officially declared to be the Golden Wattle "Acacia pycnantha". The Golden Wattle ("Acacia pycnantha") was officially proclaimed as the national floral emblem in 1988. The gold colour represents the golden wattle ("Acacia pycnantha"), which is Australia's national flower. Like many other species of wattle, "Acacia pycnantha" exudes gum when stressed. Self-incompatible, "Acacia pycnantha" cannot fertilise itself and requires cross-pollination between plants to set seed.