 Hydnellum was circumscribed by Finnish mycologist Petter Adolf Karsten in 1879 with what was then known as Hydnum suaveolens as the type species . Before then , fungi with spines ( hydnoid fungi ) had been grouped in Hydnum by Elias Fries in his 1821 work Systema <unk> . Karsten defined Hydnellum as having fruitbodies with a corky or leathery , tough cap , and a centrally attached stipe . Synonyms of Hydnellum include Calodon ( Karsten , 1881 ) , and <unk> ( Joseph Schröter , 1888 ) . 
