User:GT2004/sandbox

Description
Sexual reproduction in the Ascomycota leads to the formation of the asci, the structure that defines this fungal group and distinguishes it from other fungal phyla. The asci is a tube-shaped vessel, a meiosporangium, which contains the sexual spores produced by meiosis and which are called ascospores. Asci typically form in fruiting bodies (ascocarp). The fruiting body is the type of cleistothecia if the asci is in a rounded, closed ascocarp that has no characteristic way of opening. The chasmothecia is a subform of cleistothecia, where the asci is located in a bunch at the bottom of the fruiting body, for example, typical form of the powdery mildew (Erysiphales). Inside the fruiting body, the asci is not disordered. The sexual structures are formed in the fruiting layer of the ascocarp, the hymenium. The chasmothecia is generally spherical with no natural opening; asci with ascospores are released when a crack develops in the wall of the fruiting body. This type of fruiting body is unique among the Ascomycota. A variety of appendages may occur on the surface of the chasmothecia. These appendages are thought to act like the hooks of Velcro fastener, attaching the fruiting bodies to the host, particularly to the bark of woody plants, where they overwinter. Species identification is based on the characteristics of the chasmothecia including appendage type and ascus number and size. Chasmothecia and their appendages are barely visible with the naked eye, but seen more easily with a hand lens. Chasmothecia are spherical, typically 0.1 to 0.2 mm in diameter.