The genus Saccharomyces is similar to other yeast genera. Its species are unicellular and cylindrical, oval, or spherical in shape. They reproduce asexually through a process of budding, a new cell forming a protrusion on an existing cell, enlarging, and then breaking away. They can also reproduce sexually through the use of spores. In fact, the Saccharomyces genus is distinguished by asci, small internal structures that contain four to eight sexually produced fungal spores. All yeasts flourish in the presence of sugars and obtain food by direct absorption of nutrients.