This class is characterized by a sexual state in which the ascospores are contained within sac-like asci. The asci are contained within (or on) a variety of ascocarps including perithecia, cleistothecia, and apothecia. Also included within this phyla are the single celled yeasts. Hyphae are narrower than the Zygomycetes and are generally septate and multinucleate. This class has a dikaryon in the ascogenous hyphae. Some examples of this class are yeasts, some of the common black molds, green molds, the powdery mildews, the cup fungi, the morels, and the truffles.