AbstractThe chromosome numbers in the genusGymnostomiella, G. vernicosa n=13, and in the three members of Bartramiaceae,Anacolia sinensis n=6,Philonotis angustata n=12 andP. revoluta n=6 are reported for the first time. The counts forPhyscomitrium cyathicarpum n=52,P. repandum n=52,Bartramia hallerana n=9,B. subpellucida n=6 andPhilonotis falcata n=12 are at variance with earlier reports. Intraspecific polyploidy is recorded inPhilonotis turneranawithn=6 12. Quadrivalents are observed inPhilonotis angustata. A dimorphic bivalent, rare in monoecious bryophytes, is observed inBartramia hallerana. Unlike that of many moss species, the smallest member of the set is heteromorphic inBartramidula bartramioides,Philonotis calcarea,P. revolutaandP. turnerana.