Crucibulum parvulum, a very small new bird's nest fungus from northwestern North America

Abstract

A hitherto un-named species of Crucibulum is described and named C. parvulum. It grows in arid or in exposed areas of western Canada and northwestern United States, usually on dead plant stems. Its fruit bodies are among the smallest of the genus known; they are grey or pale buff, thin-walled, strongly obconic and have a delicate tomentum and small peridioles. These and other characters distinguish it clearly from C. laeve. C. parvulum failed to show any fertility when attempts were made to cross it with C. laeve. C. parvulum is heterothallic and tetrapolar.