Abstract
Fifteen species of Tulostomataceae from the Baja California Peninsula, Mexico were studied. A thorough macroscopic and microscopic study of the species was undertaken, including observations of spores under the scanning electron microscope. Tulostoma submembranaceum is proposed as a new species. Tulostoma exitum is a new record for America. Tulostama meridionale and T. macrocephalum are new records for Mexico. Tulostama albicans and T. pygmaeum are new records for Baja California. Tulostama utahense is proposed as a synonym of T. meridionale.