The new generic name Henfellra gen. nov. is introduced for a new species of pycnidial fungus with hyaline muriform euseptate conidia, H. muriformis sp. nov., discovered on Candelariella antennaria in Turkey. This is the first lichenicolous fungus with muriform conidia to be recognized, and the separation from non-lichenicolous pycnidial genera with muriform conidia, such as Camarosporium, is discussed. A key to the 16 lichenicolous fungi now known to occur on Candelariella species worldwide is provided, and it is noted that the generic placement of several of those will need to be reassessed as they do not appear to be congeneric with the type species of the genera in which they are currently placed. Interestingly, several rather widespread lichenicolous genera have yet to be encountered on the genus, and few are known from the three other genera of Candelariellaceae; whether this is attributable to antifungal properties of the pulvinic acid derivatives they contain merits exploration.