STUDIES ON SEXUAL STRUCTURES AND LIFE CYCLE OF GLOESTEREUM INCARNATUM
榆耳有性结构及生活史的研究

The sexual structures of Gloestereum incornatum S. Ito et Imai were investigated by means of SEM, paraffin section and nuclei staining techniques of haematoxylin and DAPI. The cross sections of a piece of lamella revealed that it consists of three layers: hair layer, trama and hymenium, Hairs on the upper surface of the pileus are long, dense and forming innumerable bundles of hairs. Trama in the middle of lamella is composed of loosely interwoven hyphae. The lower surface of hymenium is with warts on it. The club-shaped basidia have no septa and have relicula on it. Four basidiospores from sterigmata are clavate or allantoid and have relicula on it. Cystidia are cylindrical or cambiform, some of them are projecting beyond the basidia. G. incarnatum are heterothallic. Most of the basidiospores are uninucleate. Primary mycelia are also uninucleate, and cannot develop fruiting body. Clamp connections form only when two compatible monokaryotic hyphae fuse. G. incarna-tum has typical meiosis and no postmeiosis division. Chlamydospores are found either in primary mycelia or secondarmycelia. Their formation can be either intercalary or terminal. No other asexual spores are found even after inducing with temperature, light and UV. So it is belifed that G. incarnatum has no asexual cycle, the life cycle of it is completed by sexual generation.