Haleomyces oropogonicola, a New Pyrenocarpous Lichenicolous Genus and Species on Oropogon lopezii in the Neotropics

Abstract

The new lichenicolous ascomycete Haleomyces oropogonicola D. Hawksw. & Essl., gen. et sp. nov., is describedfrom thalli ofOropogon lopezii Essl. collected in Mexico and Venezuela. It is characterized by superficial perithecioid ascomata connected by stromatic tissue, periphyses, thin-walled I- asci, and colorless 1-septate ascospores. The systematic position of the fungus is problematic, but it is hesitatingly referred to Verrucariales. No lichenicolous fungi have previously been reported on Oropogon, but a synopsis of other fungi known from other alectorioid lichens is included. In the course of monographic studies of Oropogon Th.Fr. (Esslinger 1989), a distinctive lichenicolous ascomycete was discovered growing on thalli of specimens of 0. lopezii Essl. collected in the moun- tains of Mexico and Venezuela. No lichenicolous fungus has previously been reported from this lichen genus, and on examination it proved to represent a most unusual and undescribed pyrenocarpous genus and species combining features not normally ex- pected to occur in a single fungus. This new lichenicolous ascomycete is formally described here under the new generic name Hal- eomyces, in the memory of our colleague the late Mason E. Hale, Jr. (1928-1990), an outstanding lichenologist with an especial interest in macroli- chens and the neotropics.