Distribution, habitat, and relation to climatic factors of the lichen genus Ramalina in New Zealand

We present maps, based on herbarium records extensively supplemented by our own records, showing the distribution of the 14 species of Ramalina found in New Zealand (excluding the Kermadec, Chatham, and sub-antarctic islands). Species diversity is highest in two areas, eastern Northland (seven species) and coastal Otago (eight species). Only four species (R. canariensis, R. celastri, R. glaucescens, and R. unilateralis), are common to both main islands. Distribution is related to climate and altitude along a latitudinal gradient on the eastern side of New Zealand, from cooler, drier sites and higher altitudes in the south to warmer, moister sites and lower altitudes in the north. Species of Ramalina tend to be absent from sites with various combinations of high rainfall, high altitude, high water deficits, and extremes of temperature. Species reproducing asexually and sexually show similar relationships of frequency to spread, but with sexually reproducing species showing greater frequency at a given degree of spread.