The Lemon-scented Gum of Madden Grove

Pick up one of the fallen leaves, crush it, and this tree gives itself away: the lemon-scented gum carries so much citronellal in its foliage that the oil is distilled commercially and sold as insect repellent. The smell is sharp, lemony and unmistakable, and it is the fastest identification of any tree on this page. Corymbia citriodora comes from a modest patch of inland north Queensland, more than 1,500 kilometres from Richmond, and has been planted around the warm half of the world for its trunk: smooth, powdery, pale pink to white, shedding in sheets and clean of branches for most of its height. This one is 21 metres tall and 3.24 metres round, and the City of Yarra's register, which measured it in 2012, put it at 81 to 100 years then. That makes it somewhere around a century now, and the register carries it as particularly old and of outstanding size. It stands in Madden Grove, on land held as public parkland since 1862 and reserved as the Survey Paddock a generation before that, about 250 metres from the peppercorn already mapped here. The two together make a second stop on the river walk that starts at the Yarra Boulevard trees, about two kilometres away along the river path. Only the register names this specimen directly. Nobody has published a planting date for it.