The close synchrony of meiotic events within the basidiocarp of Coprinus lagopus permits the time sequence study of division stages. It takes about 16 h from the beginning of karyogamy to the completion of meiosis (zygotene to tetrad formation). Nuclear fusion and chromosome pairing occupy about 4 h, pachytene 5 h, diplotene 4 h, and all the other stages including the second meiotic division appear to be very transitory and together occupy less than 3 h. The centrosome divides at late diplotene. The entire second meiotic division takes about 1 hour and different stages overlap a great deal. The four sterigmata are formed after the completion of second division. The basidiospores mature in 8–10 h after the tetrad formation.