The lichen genus Rinodina (Physciaceae) in New Brunswick, Canada

Abstract

Fifteen species of the crustose lichen genus Rinodina are confirmed in New Brunswick, Canada. We report four corticolous species, Rinodina pachysperma, Rinodina populicola, Rinodina septentrionalis, and Rinodina tenuis, and the saxicolous Rinodina tephraspis in the province for the first time. A previous report of Rinodina granuligera is based on a specimen that we have re-identified as Rinodina cinereovirens. We note distinguishing characteristics, habitats, substrata, relative abundance, and biogeographic relationships of each species and provide an identification key and distribution maps. The most frequently occupied phorophytes (tree substrata) are Sugar Maple (Acer saccharum), Yellow Birch (Betula alleghaniensis), and Eastern White Cedar (Thuja occidentalis). Some species are closely associated with particular habitats, phorophytes, or both. For example, we found R. pachysperma only in floodplain forests dominated by Silver Maple (Acer saccharinum), and R. tenuis only on Eastern White Cedar in wet cedar-dominated stands. In contrast, we recorded Rinodina freyi on numerous phorophyte species in a relatively wide range of habitats. Other than Eastern White Cedar and Balsam Fir (Abies balsamea), conifers are rarely colonized by Rinodina species in New Brunswick. Most Rinodina species are probably not currently of conservation concern in the province. However, R. cinereovirens is known from only two collections, one dating from 1902. The other, from 2007, was on Black Ash (Fraxinus nigra) in a swamp forest next to an active peat-mining operation. The expected devastation of ash species by the invasive Emerald Ash-borer (Agrilus planipennis) is a further threat to this occurrence and to any lichens for which ash may be an important phorophyte.