Rust fungi of New Zealand—An introduction, and list of recorded species

Abstract

An overview of the rust fungi (Basidiomycota, Teliomycetes, Uredinales) is presented as an introduction towards a new rust myco‐flora for New Zealand. All species recorded from New Zealand are listed, together with details on their host plants, a reference to the first New Zealand record of each unique rust/host combination, and a separate alphabetical list of host plants and the rust fungi which parasitise them. New Zealand has a depauperate rust flora consisting of 234 recorded species, of which 54% are native. Of 22 genera recorded from New Zealand only five genera (Hamaspora, Kuehneola, Phragmidium, Puccinia, Uromyces) and three form genera (Aecidium, Caeoma, Uredo) contain native species. Only five genera (Phragmidium, Melampsora, Puccinia, Uromyces, Uromycladium) and two form genera (Aecidium, Uredo) are represented by more than two species. Melampsora contains mainly adventive species; approximately half of the Phragmidium, Puccinia, and Uromyces species and all the Uromycladium species are adventive. Some 95% of the Uredo species and all the Aecidium species are native. Only eight native rusts have spread to exotic hosts; Uredo puawhananga commonly infects some exotic, cultivated Clematis species, while Puccinia lagenophorae is sometimes troublesome on cultivars of Bellis perennis. None of the 17 exotic rusts infecting native plants is of economic or conservation concern.The widespread rusts in New Zealand are often adventive species. Only 5% of adventive rusts are confined to the South Island, but 30% are confined to the North Island. This inequity probably reflects the warmer conditions in the north, and the fact that adventive species are often of tropical origin. Of the native species, 34% occur only in the South Island and just 14% are restricted to the North Island. Since 1945, on average, more than one new adventive rust has been found per year. Most of them are of northern temperate origin, but often considered to be introduced from Australia by trans‐Tasman airflows.