Rusavskia elegans, commonly known as the elegant sunburst lichen, is a lichenized species of fungus in the genus Rusavskia, family Teloschistaceae. Recognized by its bright orange or red pigmentation, this species grows on rocks, often near bird or rodent perches. It has a circumpolar and alpine distribution. It was one of the first lichens to be used for the rock-face dating method known as lichenometry.
Rusavskia elegans
Herbarium specimen of R. elegans, showing the lobes at 40X magnification
R. elegans on the rock's surface
R. elegans on rocky islet in Gaspereau Lake
A lichen is a symbiosis of algae or cyanobacteria living among filaments of multiple fungi species, along with a yeast embedded in the cortex or "skin", in a mutualistic relationship. Lichens are important actors in nutrient cycling and act as producers which many higher trophic feeders feed on, such as reindeer, gastropods, nematodes, mites, and springtails. Lichens have properties different from those of their component organisms. They come in many colors, sizes, and forms and are sometimes plant-like, but are not plants. They may have tiny, leafless branches (fruticose); flat leaf-like structures (foliose); grow crust-like, adhering tightly to a surface (substrate) like a thick coat of paint (crustose); have a powder-like appearance (leprose); or other growth forms.
A tree covered with leafy foliose lichens and shrubby fruticose lichens
Letharia vulpina, wolf lichen, grows like a multiple-branched tuft or leafless mini-shrub, so it has a fruticose growth form.
Flavoparmelia caperata has leaf-like structures, so it is foliose.
Caloplaca marina grows like an orange crust coating the rock, so it is crustose.