Volume 26 describes three families of plants, Meliaceae, Rutaceae and Zygophyllaceae, with 61 genera and 588 species. Meliaceae is a largely tropical family and includes the well-known Toona ciliata, Red Cedar, as well as Melia azedarach, White Cedar, widely planted as an ornamental and shade tree. The largest family, Rutaceae, has 43 genera and 486 species in Australia. Some are rainforest plants, but the majority are sclerophyllous shrubs in temperate Australia, with the largest of the genera, Boronia, having 148 species. The family also includes the economically important citrus group, which includes some endemic species used in the bush food industry. Zygophyllaceae are herbs or subshrubs of mainly inland parts of Australia, and some species are very widespread. A few are declared noxious weeds, and others are reputed to be poisonous to stock.